Length of cells provisioned by Passaloecus areolatus and Passaloecus cuspidatus decreased as bore diameter increased, but volume of provisioned cells increased with increasing bore diameter. Activity of the parasitoid Omalus aneus increased length of provisioned cells. Wasp senescence did not result in increased cell length

Fricke, John M

English

ValpoScholar

The Great Lakes Entomologist 
Volume 25 
Number 2 - Summer 1992 Number 2 - Summer 
1992 
Article 8 
June 1992 
Factors Influencing Length and Volume of Cells Provisioned by 
Two Passaloecus Species (Hymemoptera: Sphecidae) 
John M. Fricke 
Concordia College 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Fricke, John M. 1992. "Factors Influencing Length and Volume of Cells Provisioned by Two Passaloecus 
Species (Hymemoptera: Sphecidae)," The Great Lakes Entomologist, vol 25 (2) 
Available at: https://scholar.valpo.edu/tgle/vol25/iss2/8 
This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. 
It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. 
For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 
1992 THE GREAT LAKES ENTOMOLOGIST 107 
FACTORS INFLUENCING LENGTH AND VOLUME OF CELLS PROVISIONED 
BY TWO PASSALOECUS SPECIES (HYMEMOPTERA: SPHECIDAE) 
John M. Fricke1 
ABSTRACT 
Length 
of cells provisioned 
by Passaloecus areolatus and Passaloecus 
cuspidatus decreased as bore diameter increased, but volume of provisioned 
cells increased with increasing bore diameter. Activity of the parasitoid Oma­
lus aneus increased length of provisioned cells. Wasp senescence did not result 
in increased cell length. 
Danks (1971) suggested that the availability of nesting sites was one of the 
factors limiting populations of wood inhabiting aculeate Hymenoptera. If this 
is 
true, 
it should be possible to identify strategies used to optimize available 
nesting material. One of these strategies could be the decrease of cell length as 
bore diameter increases. Such a strategy would increase the number oJ cells 
possible in a g ven est. Fye (1965), Krombein (1967) and Vincent (1978) gave 
bore diameter and cell length data for cells provisioned by Passaloecus cuspi­
datus Smith. Krombein (1967) reported 58 provisioned cells from 3.2 mm bore 
diameter trap-nests (mean length, 16.3 mm; range, 8-52 mm.); four cells from 
4.8 mm bore diameter were 7, 8, 13, and 126 mm long; and one 6.4 mm bore 
diameter trap-nest had four cells 6, 7, 7. and 9 mm long, respectively. Fye (1965) 
reported a 6.4 mm bore diameter trap-nest of four cells, with a mean cell length 
of 15 mm. Vincent (1978) reported data from 83 soda straw nests with 4.0 mm 
bore diameters. One hundred-eleven female cells had a mean l ngth of 10.09 ± 
2.19 mm and 110 male cells had a mean length of 8.82 ± 2.16 mm. These data 
suggest that Passaloecus spp. would optimize nesting material by decreasing 
cell length as bore diameter increases. 
METHODS AND MATERIALS 
To test whether Passaloecus spp. optimize their use of bore volume, trap­
nests 
of several bore diameters were made available 
as nesting sites on the 
campus of Concordia College from 1984 through 1987. Trap-nest design has 
been previously described (Fricke 1991). Cell length and volume data were 
collected from trap-nests provisioned by Passaloecus annulatus (Say), P. 
areolatus Vincent, P. cuspidatus Smith, and P. monilicornis Dahlbom. Cell 
length was determined by measuring the distance from he innermost surface 
of a cell to the exterior surface of the cell closure. Cell volume was determined 
INatural Science and Mathematics Division, Concordia College, Ann Arbor. MI 
48105. 
1
Fricke: Factors Influencing Length and Volume of Cells Provisioned by Two
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108 
12.79 
THE GREAT LAKES ENTOMOLOGIST Vol. 25, No.2 
Table 1. Cell length data from trap-nests provisioned by Pas aloecus areolatus and P. cuspi­
datus. 1984-1987. 
Bore Number Cell Median Mean 
Passaloecus 
spp. (mml of Cells 
Length Cell Length Cell Length 
areolatus 2.0 73 7.5-41 13.19 14.33±5.31 
2.4 30 7- 6 13.19 15.57±7.27 
12.96 4 34±5.29 
3.2 210 6-82 12.73 14.17±8.30
cuspidatus 
4.0 180 5-101 10.03 15.09±17.00 4.8 95 5-116 10.23 20.58±26.33 
by using the fonnula for a cylinder and the length and bore diameter of each 
respective cell_ 
RESULTS AND DISCUSSION 
Lengths of provisioned cells produced by P. areolatus nd P. cuspidatus 
were varied and skewed. This should be expected since one tail of the distribu­
tion of provisioned cell length is closed (no cell can have a length shorter than 
omm) and the open end of the distribution is limited by the actual length of 
the 
trap-nest bore 
(120 mm). Data for P. areolatus and P. cuspidatus are 
summarized in Table 1. Ranges and medians for the e respective species and 
trap-nest bore diameter classes show median cell lengths much shorter than 
mid-point cell lengths of respective ranges. In no mal distributions equal pro­
portions of measurements above and below the mean would be expected. How­
ever, th  percentage of cell lengths shorter an respective mean cell lengths 
for P. areolatus were 71.4, 68.5, and 73.3%. For P. cuspidatus these values 
were respectively 72.5, 61, 80, and 81.5%. 
Mean cell lengths are longer than median cell lengths and variances are 
exceptionally high. This reflects the statistical effect of a small number of 
provisioned cells of extraordinary length. These cells were usually found to be,
but not 
limited to. 
the last provisioned cell in a trap nest. Frequently such a 
trap-nest did not have a vestibular cell, although in a few cases an extraordi­
narily long cell was followed by a vestibular cell. To eliminate the statistical 
effects of cells of extraordinary length, a 10% exclusion rule was applied to the 
analysis of cell length data. For each species, 10% of the cell length values 
from the open end of the distributions were excluded in subsequent analysis. 
The r sults of this analysis are given in Table 2. 
With the 
application 
of the 10% exclusion rule mean values are clearly 
more representative of cell length measurements and demonstrate an inverse 
relationship between bore diameter and cell lengths. One-way ANOVA for 
differences in cell lengths associated with differences in bore diameter were 
significant for P. areolatus (F 3.30337, df = 134, p < .01) and for P. cuspida­
tus (F = 19.51697, df = 472, p < .001). However, these mean values do not 
reflect he extreme variation observed in provisioned cell le gth and we can 
only speculate on possible causes for such variation. One possible cause could 
be 
a declining prey population. 
As prey numbers decrease. additional time n  
enerw. are expended during provisioning. In this case an optimal closure or 
partition strategy 
would be reduction of 
time required to move from the trap­
nest 
bore opening 
to the partition or closure. A partition or closure placed 
2
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1992 THE GREAT LAKES ENTOMOLOGIST 109 
Table 2. Cell length data from trap-nests provisioned by Passaloecus areolatus and P. cuspi­
datus, 1984-1987 using a 10% exclusion rule.* 
Bore Number Cell Median 
Passaloecus spp. (mm) of Cells Length Cell Length 
41 
9-25.5 14.17 areolatus 2.0 71 7.5-25 13.06 13.51±3.79 2.4 25 7-21 12.81 12.68 ± 3.26 
2.4 38 8-22 12.89 13.43±3.19 
3.2 195 6-23 11.93 2. 9±3.45
cuspidatus 4.0 164 5-23 9.90 10.33±2.38 
4.8 79 5-23 9.825 9.47±2.72 
*Ten percent of the ll length values from the open end of cell length distributions were 
excluded in these analyses. 
closer to the hore opening will produce a cell of disproportionate length and 
volume. 
Previous research on P ssal ecus has made no reference to cell volume, 
and 
no anaylses have heen done on relationships 
between number of prey per 
cell, cell length, cell volume and bore diameter. If Passaloecus spp. made 
maximum use of available bore space, constant volume for cells from trap­
nests 
of different bore diameters should be observed. This hypothesis was 
evaluated 
by determining cell volume for provisioned cells of mean cell length 
from each bore diameter used by P. areolatus and P. cuspidatus (Table 3). 
These data show that cell volume increased as bore diameter increased for 
both 
species. 
A related question is whether or 
not increased cell volume is associated 
with a larger number of provisions. Data were available from 3.2 and 4.0 mm 
bore trap-nests provisioned by P. cuspidatus with Myzus monardae (Davis) 
(Aphididael. Cells with extraordinary length and cells in which larval feeding 
had 
occurred prior were excluded from this analysis. Such feeding would 
reduce 
the number of aphids by an uncertain amount. Ranges and means for 
number of aphids per cell, cell length, and cell volume were determined for 58 
cells of 3.2 mm bore trap-nests and 59 cells from 4.0 mm bore trap-nests (Table 
4). 
There was no significant difference in 
the number of aphids provisioned in 
3.2 and 4.0 mm bore trap-nests. However, differences in cell length and vol­
ume were signficant. As bore diameter increased, cell length decreased and 
cell volume increased. While no ata were collected on actual volume of aphid 
provisions, a relative index to utilization of available space is cell volume 
(mm3)/aphid. The index for 3.2 mm bore trap-nests was 2.895 and for 4.0 mm 
bore trap-nests, 3.336. If an equal volume per provisioned aphid is assumed, 
Table 3. Trap-nest bore diameters and provisioned cell volume for two Passala cus spp. 
Passalcecus spp. provisioned cell volume 
(mm3)Bore 
(mm) areolatus cuspidatus 
1.6 30.42± 7.66 
2.0 42.44±1l.90 
2.4 57.36±14.77 60.76±14.43 
3.2 100.53 ± 28.87 
·4,0 
131.57 ± 39.08 
4.8 182.22 ± 60.98 
3
Fricke: Factors Influencing Length and Volume of Cells Provisioned by Two
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110 THE GREAT LAKES ENTOMOLOGIST Vol. 25, No.2 
Table 4. Number of aphids [Myzus m01l.ardae (Aphididael] provisioned per cell, cell length 
and cell volume in 3.2nun bore and 4.0 nun bore trap-nests provisioned by Passaloecus cuspi­
datus, 1987. 
tIll) statistic 
Bore Range Mean t value df prob 
II 
of 3.2 
22 to 66 35.81 ± 10.25 
aphids 1.3098 115 p>.05 
per 
cell 4.0 14 
to 74 38.67 ± 13.03 
3.2 ± 3.29 
length 4.2796 115 p<.0005 
(nun) 4.0 6 to 23 1O.27± 3.28 
Cell 3.2 56.30 to 184.98 103.67 ± 26.49 
volume 3.9331 115 p<.0005 
(nun3) 4.0 75.40 to 289.03 129.02±41.19 
these indices show a more efficient use of the 3.2 mm bore trap-nests. These 
results agree with t e subjective observation that the free space above the 
aphid provisions was larger in 4.0 mm bores. 
Scatter 
plots of number of aphids provisioned per cell 
and cell volume for 
3.2 and 4.0 rom bore trap-nest are given in Figures 1 and 2. Simple linear 
regression of cell volume on number of aphids provisoned per cell gave the 
respective regression equations: (Y = 54.88 + 1.36X, r = 0.53) for 3.2 mm 
bores and (Y = 86.75 + 1.09X, r = 0.35) for 4.0 mm bores. Cell volume is 
weakly related to the number of aphids provisioned. In the case of 3.2 rom 
bores, 25% of the variance of cell volume is accounted for by the variance of 
the 
number of aphids provisioned; 
in 4.0 mm bores only 12.25% of the vari­
ance of cell volume is accounted for by the variance of the number of aphids 
provisioned. Cell volume is not greatly affected by the number of aphids 
provisioned. 
In 
addition 
to bore diameter, several other factors could contribute to 
v riationsin length of provisioned cells. Wasp behavior, influencing the place­
ment of cell partitions and closures, could be altered by age, prey availability, 
proximity of prey, weather conditions, competition for nesting sites, and the 
activity of parasites. 1b determine whether extraordinary cell lengths were a 
result of wasp senescence, cell length data for trap-nests with known closure 
dates 
were examined from P. cuspidatus trap-nests of 1984 and 1987. 
If 
extraordinary cell length is a result of senescence, increased length would be 
noted in late-season nests. Provisioned cells of extraordinary length (24 116 
rom) were found in trap-nests provisioned throughout P. cuspidatus nesting 
season, and in all but three cases the extraordinary cell was the last cell 
provisioned (Table 5). Senescence can thus be excluded as a principal factor 
contributing to increased cell length. 
Another possible cause for increased cell length is the activity of para­
sites. Data from P. cuspidatus nes s of 1984 were examined for evidence that 
activity of Omalus aeneus (Fabricius) (Chrysididae) contributed to increased 
cell length. Ranges of provisioned cell length from trap-nests of respective 
bore diameter classes were as follows: 3.2 rom (6 to 31 mm, n = 79); 4.0 mm (6 
to 101 
rom, n 
= 29); 4.8 rom (5 to 116 mm, n = 52); and 6.4 mm (5 to 20 mm, n 
= 10). Cell length data for eight of 170 cells (approximately 5% of all values) 
were excluded in the analyses of these data because they were characterized as 
cells with extraordinary length. No cell lengths were excluded from 3.2 mm 
bore data, 3 cell lengths (56, 94, and 101 mm) were excluded from 4.0 rom bore 
data, 
and 5 cell lengths 
(56,72,78,108, and 116 mm) were excluded from 4.8 
4
The Great Lakes Entomologist, Vol. 25, No. 2 [1992], Art. 8
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1992 
190 
111 THE GREAT LAKES ENTOMOLOGIST 
+ 
,....... 170 

I'") 
+
+ + +E 150E 
"-' ++ 
<I.) 130 + +
+E 
:;, + + (5 110 + +> + ++(j) 90 ++ u * + +++ + + + + 
70 *++ + + 
50~----~+~----~----~------r-----~ 
20 30 40 50 60 70 
Number of Aphids Provisioned Per Cell 
Figure 1. Scatter plot of number of aphids provisioned per cell and cell volumes (mm3) 
for Passaloecus cuspidatus 3.2 mm bore trap-nests, 1987. 
300 + 
260 
++ 
220 + ++ + +(L) + + + E 
:;, 180 (5 
> 140 (j) 
u 
100 

60 

10 
+ 
+ 
20 30 40 50 60 70 S0 
Number of Aphids Provisioned Per Cell 
Figure 2. Scatter plot of number of aphids provisioned per cell and cell volumes (mm3) 
for Passaloecus cuspidatus 4.0 mm bore trap-nests, 1987. 
5
Fricke: Factors Influencing Length and Volume of Cells Provisioned by Two
Published by ValpoScholar, 1992
112 THE GREAT LAKES ENTOMOlOGIST Vol. 25, o.2 
Table 5. Seasonal distribution of Passaloecus cuspidatus cells of extraordinary length. 
Cell length (mm)Date of Bore 
closure (mm) 1 2 3 4 5 6 7 8 9 
11 
6-18-84 4.0 15 101* 
6-20-84 4.8 116* 
6-21-84 4.8 8 108* 
7-09-84 4.0 7 56* 
7-16-84 4.8 17 24* 17 56* 
7-16-84 4.8 14 14 72* 
8-07-84 4.8 14 12 78* 
6-15-87 4.0 10 10 72* 
6-19-87 4.0 13 97* 
6-19-87 5.6 7 7 101* 
7-03-87 3.2 19 19 12 67* 
7-06-87 4.0 7 7 8.5 14 7 7 7.5 13 46* 
7-08-87 4.0 13 10.5 15.5 10 10 67* 
7-08-87 3.2 47* 
7-08-87 3.2 16 47* 
7-08-87 4.8 10 13 77* 
7-08-87 3.2 23 25* 51* 
7-10-87 4.0 12 15 14 59* 
7-10-87 4.0 10 8 8 94* 
7-20-87 4.8 9 105* 
7-20-87 4.0 10 9 46* 
7-20-87 4.8 35* 88* 
7-20-87 4.8 12 12 91* 
7-20-87 4.8 13 13 44* 
7-24-87 4.0 23 75* 
7-27-87 3.2 12 16 17.5 82* 
*extraordinary 
cell 
length 
Table 6. Cell l ngth data from 1984 Passaloecus cuspidatus nests parasitized by Omalus 
aeneus. 
Cell length (=)Date of Bore 

closure (mm) 1 2 3 4 5 6 7 8 9 10 

6-14-84 

6-17-84 3.2 12* 11 14 12 12 10* 10 11 

6-18-84 3.2 18* 20* 27* 24* 

6-30-84 3.2 18 19 13 9* 

7-16-84 3.2 22* 15 

7-24-84 3.2 27 8 12* 

6-18-84 4.0 32* 6 9* 

6-19-84 4.0 25* 9 

6-21-84 4.0 11 15* 

6-26-84 4.0 12 1  9 9 8* 8 

7-03-84 4.0 8* 10 

6-12-84 4.8 7* 

? 4.8 10* 10* 
6-21-84 4.8 8* 108 
6-30-84 4.8 10* 10 
7-16-84 4.8 14* 14 72 
7-16-84 4.8 17* 24 17* 56 
6-18-84 6.4 6* 6 6* 6 5* 6 6 6 5 21 
*parasitized cell 
6
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1992 THE GREAT LAKES ENTOMOLOGIST 113 
Table 7. Cell length data for cells from non-parasitized trap-nests and parasitized trap·nests 
provisioned by Passaloecus cuspidatus, 1984. 
Mean Provisioned Cell Length (mm), Standard Deviation, 
and Number of Cells in Each Class 
Bore 
(mm) All trap-nests 
in bore class 
Trap'nests free 
of parasites 
Trap-nests 
wi 
parasites 
Paratized 
cells only 
3.2 s 
n 
5.20 
79 
12.42 
3.91 
57 
16.00 
6.74 
22 
6.91 
10 
4.0 
x 
s 
n 
6.10 
26 
4.83 
10 
6.75 
16 
9.26 
6 
11.63 
4.8 s 4.11 3.37 4.78 3.64 
n 47 36 11 8 
7.3 7.30 5.67 
6.4 s 4.58 4.58 0.47 
n 10 10 3 
i mean; s = standard deviaiton; n number in class. 
mm bore data. No parasitized cells were noted among excluded cells. Eighteen 
of 53 provisioned trapnests were parasitized and contained 27 parasitized 
cells. Parasitized tr p·nests contained 32 cells free of parasites. Cell length 
data 
for these 
parasitized trap-nests is given in Table 6. Mean cell length of all 
bore classes were determined for: all cells, cells from trap-nests free of para· 
sites, cells from parasitized trap nests, and parasitized cells (Table 7). 
Although sample sizes were relatively small these data show that parasit· 
ism of P. cupidatus cells by O. aeneus results in increased cell length in trap· 
nests 
with bore diameters equal 
to or less than 4.8 mm. The t(II) test for 
differences in mean cell lengths between trap·nests without parasites and 
trap-nests with parasites was significant for 3.2 mm trap-nests (t = 2.343, df 
= 77, P < .025) and for 4.8 mm trap-nests (t 2.5563, df= 45, P < .005). 
Parasitized cells from 3.2, 4.0, and 4.8 mm bores had cell lengths which were 
respectively 51%, 26%, and 31  lo ger than cells from nonparasitized trap­
nests. In a single 6,4 mm bore trap-nest, parasitism did not result in increased 
cell lengths. 
Passaloecus cuspidatus does not maximally use trap-nest bore volume. 
Larger bore diameter trap-nests contained cells with decreased length, while 
cells parasitized by Omalus aenus were longer than non-parasitized cells. Vol­
ume of provisioned cells increased with increased bore diameter, but number 
of aphids provisioned did not increase proportionately with increased cell 
volume. Additionally, wasp senescence did not result in increased length of 
provisioned cells. 
LITERATURE CITED 
Danks, J. V. 1971. Biology of some stem-n sting aculeate Hymenoptera. Trans. Roy. 
Entomol. 
Soc. London. 
122:323-399. 
Fricke, J. M. 1991. Trap-nest bore diameter preferences among sympatric Passaloecus 
spp. (Hymenoptera: Sphecidae). Great Lakes Entomol. 24:123-125. 
Fye, R. E. 1965. The biology of the Vespidae. Pompilidae and Sphecidae from trapn sts 
in northwestern 
Ontario. 
Canadian Entomol. 97:716-744. 
7
Fricke: Factors Influencing Length and Volume of Cells Provisioned by Two
Published by ValpoScholar, 1992
114 THE GREAT LAKES ENTOMOLOGIST Vol. 25, No.2 
Krombein, K. V. 1967. Trap-nesting wasps and bees: Life histories, nests, and asso­
ciates.Smithsonian Press, Washington D.C. vi + 570 pp. 
Vincent, D. L. 1978. A revision of the genus Passaloecus (Hymenoptera: Sphecidae; in 
America north of Mexico. Wasmann J. BioI. 36:127-198. 
8
The Great Lakes Entomologist, Vol. 25, No. 2 [1992], Art. 8
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Factors Influencing Length and Volume of Cells Provisioned by Two \u3ci\u3ePassaloecus\u3c/i\u3e Species (Hymemoptera: Sphecidae)

Valparaiso University

The Great Lakes Entomologist Volume 25 Number 2 - Summer 1992 Number 2 - Summer 1992 Article 8 June 1992 Factors Influencing Length and Volume of Cells Provisioned by Two Passaloecus Species (Hymemoptera: Sphecidae) John M. Fricke Concordia College Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Fricke, John M. 1992. "Factors Influencing Length and Volume of Cells Provisioned by Two Passaloecus Species (Hymemoptera: Sphecidae)," The Great Lakes Entomologist, vol 25 (2) Available at: https://scholar.valpo.edu/tgle/vol25/iss2/8 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 1992 THE GREAT LAKES ENTOMOLOGIST 107 FACTORS INFLUENCING LENGTH AND VOLUME OF CELLS PROVISIONED BY TWO PASSALOECUS SPECIES (HYMEMOPTERA: SPHECIDAE) John M. Fricke1 ABSTRACT Length of cells provisioned by Passaloecus areolatus and Passaloecus cuspidatus decreased as bore diameter increased, but volume of provisioned cells increased with increasing bore diameter. Activity of the parasitoid Oma­lus aneus increased length of provisioned cells. Wasp senescence did not result in increased cell length. Danks (1971) suggested that the availability of nesting sites was one of the factors limiting populations of wood inhabiting aculeate Hymenoptera. If this is true, it should be possible to identify strategies used to optimize available nesting material. One of these strategies could be the decrease of cell length as bore diameter increases. Such a strategy would increase the number oJ cells possible in a g ven est. Fye (1965), Krombein (1967) and Vincent (1978) gave bore diameter and cell length data for cells provisioned by Passaloecus cuspi­datus Smith. Krombein (1967) reported 58 provisioned cells from 3.2 mm bore diameter trap-nests (mean length, 16.3 mm; range, 8-52 mm.); four cells from 4.8 mm bore diameter were 7, 8, 13, and 126 mm long; and one 6.4 mm bore diameter trap-nest had four cells 6, 7, 7. and 9 mm long, respectively. Fye (1965) reported a 6.4 mm bore diameter trap-nest of four cells, with a mean cell length of 15 mm. Vincent (1978) reported data from 83 soda straw nests with 4.0 mm bore diameters. One hundred-eleven female cells had a mean l ngth of 10.09 ± 2.19 mm and 110 male cells had a mean length of 8.82 ± 2.16 mm. These data suggest that Passaloecus spp. would optimize nesting material by decreasing cell length as bore diameter increases. METHODS AND MATERIALS To test whether Passaloecus spp. optimize their use of bore volume, trap­nests of several bore diameters were made available as nesting sites on the campus of Concordia College from 1984 through 1987. Trap-nest design has been previously described (Fricke 1991). Cell length and volume data were collected from trap-nests provisioned by Passaloecus annulatus (Say), P. areolatus Vincent, P. cuspidatus Smith, and P. monilicornis Dahlbom. Cell length was determined by measuring the distance from he innermost surface of a cell to the exterior surface of the cell closure. Cell volume was determined INatural Science and Mathematics Division, Concordia College, Ann Arbor. MI 48105. 1Fricke: Factors Influencing Length and Volume of Cells Provisioned by TwoPublished by ValpoScholar, 1992108 12.79 THE GREAT LAKES ENTOMOLOGIST Vol. 25, No.2 Table 1. Cell length data from trap-nests provisioned by Pas aloecus areolatus and P. cuspi­datus. 1984-1987. Bore Number Cell Median Mean Passaloecus spp. (mml of Cells Length Cell Length Cell Length areolatus 2.0 73 7.5-41 13.19 14.33±5.31 2.4 30 7- 6 13.19 15.57±7.27 12.96 4 34±5.29 3.2 210 6-82 12.73 14.17±8.30cuspidatus 4.0 180 5-101 10.03 15.09±17.00 4.8 95 5-116 10.23 20.58±26.33 by using the fonnula for a cylinder and the length and bore diameter of each respective cell_ RESULTS AND DISCUSSION Lengths of provisioned cells produced by P. areolatus nd P. cuspidatus were varied and skewed. This should be expected since one tail of the distribu­tion of provisioned cell length is closed (no cell can have a length shorter than omm) and the open end of the distribution is limited by the actual length of the trap-nest bore (120 mm). Data for P. areolatus and P. cuspidatus are summarized in Table 1. Ranges and medians for the e respective species and trap-nest bore diameter classes show median cell lengths much shorter than mid-point cell lengths of respective ranges. In no mal distributions equal pro­portions of measurements above and below the mean would be expected. How­ever, th  percentage of cell lengths shorter an respective mean cell lengths for P. areolatus were 71.4, 68.5, and 73.3%. For P. cuspidatus these values were respectively 72.5, 61, 80, and 81.5%. Mean cell lengths are longer than median cell lengths and variances are exceptionally high. This reflects the statistical effect of a small number of provisioned cells of extraordinary length. These cells were usually found to be,but not limited to. the last provisioned cell in a trap nest. Frequently such a trap-nest did not have a vestibular cell, although in a few cases an extraordi­narily long cell was followed by a vestibular cell. To eliminate the statistical effects of cells of extraordinary length, a 10% exclusion rule was applied to the analysis of cell length data. For each species, 10% of the cell length values from the open end of the distributions were excluded in subsequent analysis. The r sults of this analysis are given in Table 2. With the application of the 10% exclusion rule mean values are clearly more representative of cell length measurements and demonstrate an inverse relationship between bore diameter and cell lengths. One-way ANOVA for differences in cell lengths associated with differences in bore diameter were significant for P. areolatus (F 3.30337, df = 134, p < .01) and for P. cuspida­tus (F = 19.51697, df = 472, p < .001). However, these mean values do not reflect he extreme variation observed in provisioned cell le gth and we can only speculate on possible causes for such variation. One possible cause could be a declining prey population. As prey numbers decrease. additional time n  enerw. are expended during provisioning. In this case an optimal closure or partition strategy would be reduction of time required to move from the trap­nest bore opening to the partition or closure. A partition or closure placed 2The Great Lakes Entomologist, Vol. 25, No. 2 [1992], Art. 8https://scholar.valpo.edu/tgle/vol25/iss2/81992 THE GREAT LAKES ENTOMOLOGIST 109 Table 2. Cell length data from trap-nests provisioned by Passaloecus areolatus and P. cuspi­datus, 1984-1987 using a 10% exclusion rule.* Bore Number Cell Median Passaloecus spp. (mm) of Cells Length Cell Length 41 9-25.5 14.17 areolatus 2.0 71 7.5-25 13.06 13.51±3.79 2.4 25 7-21 12.81 12.68 ± 3.26 2.4 38 8-22 12.89 13.43±3.19 3.2 195 6-23 11.93 2. 9±3.45cuspidatus 4.0 164 5-23 9.90 10.33±2.38 4.8 79 5-23 9.825 9.47±2.72 *Ten percent of the ll length values from the open end of cell length distributions were excluded in these analyses. closer to the hore opening will produce a cell of disproportionate length and volume. Previous research on P ssal ecus has made no reference to cell volume, and no anaylses have heen done on relationships between number of prey per cell, cell length, cell volume and bore diameter. If Passaloecus spp. made maximum use of available bore space, constant volume for cells from trap­nests of different bore diameters should be observed. This hypothesis was evaluated by determining cell volume for provisioned cells of mean cell length from each bore diameter used by P. areolatus and P. cuspidatus (Table 3). These data show that cell volume increased as bore diameter increased for both species. A related question is whether or not increased cell volume is associated with a larger number of provisions. Data were available from 3.2 and 4.0 mm bore trap-nests provisioned by P. cuspidatus with Myzus monardae (Davis) (Aphididael. Cells with extraordinary length and cells in which larval feeding had occurred prior were excluded from this analysis. Such feeding would reduce the number of aphids by an uncertain amount. Ranges and means for number of aphids per cell, cell length, and cell volume were determined for 58 cells of 3.2 mm bore trap-nests and 59 cells from 4.0 mm bore trap-nests (Table 4). There was no significant difference in the number of aphids provisioned in 3.2 and 4.0 mm bore trap-nests. However, differences in cell length and vol­ume were signficant. As bore diameter increased, cell length decreased and cell volume increased. While no ata were collected on actual volume of aphid provisions, a relative index to utilization of available space is cell volume (mm3)/aphid. The index for 3.2 mm bore trap-nests was 2.895 and for 4.0 mm bore trap-nests, 3.336. If an equal volume per provisioned aphid is assumed, Table 3. Trap-nest bore diameters and provisioned cell volume for two Passala cus spp. Passalcecus spp. provisioned cell volume (mm3)Bore (mm) areolatus cuspidatus 1.6 30.42± 7.66 2.0 42.44±1l.90 2.4 57.36±14.77 60.76±14.43 3.2 100.53 ± 28.87 ·4,0 131.57 ± 39.08 4.8 182.22 ± 60.98 3Fricke: Factors Influencing Length and Volume of Cells Provisioned by TwoPublished by ValpoScholar, 1992110 THE GREAT LAKES ENTOMOLOGIST Vol. 25, No.2 Table 4. Number of aphids [Myzus m01l.ardae (Aphididael] provisioned per cell, cell length and cell volume in 3.2nun bore and 4.0 nun bore trap-nests provisioned by Passaloecus cuspi­datus, 1987. tIll) statistic Bore Range Mean t value df prob II of 3.2 22 to 66 35.81 ± 10.25 aphids 1.3098 115 p>.05 per cell 4.0 14 to 74 38.67 ± 13.03 3.2 ± 3.29 length 4.2796 115 p<.0005 (nun) 4.0 6 to 23 1O.27± 3.28 Cell 3.2 56.30 to 184.98 103.67 ± 26.49 volume 3.9331 115 p<.0005 (nun3) 4.0 75.40 to 289.03 129.02±41.19 these indices show a more efficient use of the 3.2 mm bore trap-nests. These results agree with t e subjective observation that the free space above the aphid provisions was larger in 4.0 mm bores. Scatter plots of number of aphids provisioned per cell and cell volume for 3.2 and 4.0 rom bore trap-nest are given in Figures 1 and 2. Simple linear regression of cell volume on number of aphids provisoned per cell gave the respective regression equations: (Y = 54.88 + 1.36X, r = 0.53) for 3.2 mm bores and (Y = 86.75 + 1.09X, r = 0.35) for 4.0 mm bores. Cell volume is weakly related to the number of aphids provisioned. In the case of 3.2 rom bores, 25% of the variance of cell volume is accounted for by the variance of the number of aphids provisioned; in 4.0 mm bores only 12.25% of the vari­ance of cell volume is accounted for by the variance of the number of aphids provisioned. Cell volume is not greatly affected by the number of aphids provisioned. In addition to bore diameter, several other factors could contribute to v riationsin length of provisioned cells. Wasp behavior, influencing the place­ment of cell partitions and closures, could be altered by age, prey availability, proximity of prey, weather conditions, competition for nesting sites, and the activity of parasites. 1b determine whether extraordinary cell lengths were a result of wasp senescence, cell length data for trap-nests with known closure dates were examined from P. cuspidatus trap-nests of 1984 and 1987. If extraordinary cell length is a result of senescence, increased length would be noted in late-season nests. Provisioned cells of extraordinary length (24 116 rom) were found in trap-nests provisioned throughout P. cuspidatus nesting season, and in all but three cases the extraordinary cell was the last cell provisioned (Table 5). Senescence can thus be excluded as a principal factor contributing to increased cell length. Another possible cause for increased cell length is the activity of para­sites. Data from P. cuspidatus nes s of 1984 were examined for evidence that activity of Omalus aeneus (Fabricius) (Chrysididae) contributed to increased cell length. Ranges of provisioned cell length from trap-nests of respective bore diameter classes were as follows: 3.2 rom (6 to 31 mm, n = 79); 4.0 mm (6 to 101 rom, n = 29); 4.8 rom (5 to 116 mm, n = 52); and 6.4 mm (5 to 20 mm, n = 10). Cell length data for eight of 170 cells (approximately 5% of all values) were excluded in the analyses of these data because they were characterized as cells with extraordinary length. No cell lengths were excluded from 3.2 mm bore data, 3 cell lengths (56, 94, and 101 mm) were excluded from 4.0 rom bore data, and 5 cell lengths (56,72,78,108, and 116 mm) were excluded from 4.8 4The Great Lakes Entomologist, Vol. 25, No. 2 [1992], Art. 8https://scholar.valpo.edu/tgle/vol25/iss2/81992 190 111 THE GREAT LAKES ENTOMOLOGIST + ,....... 170 I'") ++ + +E 150E "-' ++ <I.) 130 + ++E :;, + + (5 110 + +> + ++(j) 90 ++ u * + +++ + + + + 70 *++ + + 50~----~+~----~----~------r-----~ 20 30 40 50 60 70 Number of Aphids Provisioned Per Cell Figure 1. Scatter plot of number of aphids provisioned per cell and cell volumes (mm3) for Passaloecus cuspidatus 3.2 mm bore trap-nests, 1987. 300 + 260 ++ 220 + ++ + +(L) + + + E :;, 180 (5 > 140 (j) u 100 60 10 + + 20 30 40 50 60 70 S0 Number of Aphids Provisioned Per Cell Figure 2. Scatter plot of number of aphids provisioned per cell and cell volumes (mm3) for Passaloecus cuspidatus 4.0 mm bore trap-nests, 1987. 5Fricke: Factors Influencing Length and Volume of Cells Provisioned by TwoPublished by ValpoScholar, 1992112 THE GREAT LAKES ENTOMOlOGIST Vol. 25, o.2 Table 5. Seasonal distribution of Passaloecus cuspidatus cells of extraordinary length. Cell length (mm)Date of Bore closure (mm) 1 2 3 4 5 6 7 8 9 11 6-18-84 4.0 15 101* 6-20-84 4.8 116* 6-21-84 4.8 8 108* 7-09-84 4.0 7 56* 7-16-84 4.8 17 24* 17 56* 7-16-84 4.8 14 14 72* 8-07-84 4.8 14 12 78* 6-15-87 4.0 10 10 72* 6-19-87 4.0 13 97* 6-19-87 5.6 7 7 101* 7-03-87 3.2 19 19 12 67* 7-06-87 4.0 7 7 8.5 14 7 7 7.5 13 46* 7-08-87 4.0 13 10.5 15.5 10 10 67* 7-08-87 3.2 47* 7-08-87 3.2 16 47* 7-08-87 4.8 10 13 77* 7-08-87 3.2 23 25* 51* 7-10-87 4.0 12 15 14 59* 7-10-87 4.0 10 8 8 94* 7-20-87 4.8 9 105* 7-20-87 4.0 10 9 46* 7-20-87 4.8 35* 88* 7-20-87 4.8 12 12 91* 7-20-87 4.8 13 13 44* 7-24-87 4.0 23 75* 7-27-87 3.2 12 16 17.5 82* *extraordinary cell length Table 6. Cell l ngth data from 1984 Passaloecus cuspidatus nests parasitized by Omalus aeneus. Cell length (=)Date of Bore closure (mm) 1 2 3 4 5 6 7 8 9 10 6-14-84 6-17-84 3.2 12* 11 14 12 12 10* 10 11 6-18-84 3.2 18* 20* 27* 24* 6-30-84 3.2 18 19 13 9* 7-16-84 3.2 22* 15 7-24-84 3.2 27 8 12* 6-18-84 4.0 32* 6 9* 6-19-84 4.0 25* 9 6-21-84 4.0 11 15* 6-26-84 4.0 12 1  9 9 8* 8 7-03-84 4.0 8* 10 6-12-84 4.8 7* ? 4.8 10* 10* 6-21-84 4.8 8* 108 6-30-84 4.8 10* 10 7-16-84 4.8 14* 14 72 7-16-84 4.8 17* 24 17* 56 6-18-84 6.4 6* 6 6* 6 5* 6 6 6 5 21 *parasitized cell 6The Great Lakes Entomologist, Vol. 25, No. 2 [1992], Art. 8https://scholar.valpo.edu/tgle/vol25/iss2/81992 THE GREAT LAKES ENTOMOLOGIST 113 Table 7. Cell length data for cells from non-parasitized trap-nests and parasitized trap·nests provisioned by Passaloecus cuspidatus, 1984. Mean Provisioned Cell Length (mm), Standard Deviation, and Number of Cells in Each Class Bore (mm) All trap-nests in bore class Trap'nests free of parasites Trap-nests wi parasites Paratized cells only 3.2 s n 5.20 79 12.42 3.91 57 16.00 6.74 22 6.91 10 4.0 x s n 6.10 26 4.83 10 6.75 16 9.26 6 11.63 4.8 s 4.11 3.37 4.78 3.64 n 47 36 11 8 7.3 7.30 5.67 6.4 s 4.58 4.58 0.47 n 10 10 3 i mean; s = standard deviaiton; n number in class. mm bore data. No parasitized cells were noted among excluded cells. Eighteen of 53 provisioned trapnests were parasitized and contained 27 parasitized cells. Parasitized tr p·nests contained 32 cells free of parasites. Cell length data for these parasitized trap-nests is given in Table 6. Mean cell length of all bore classes were determined for: all cells, cells from trap-nests free of para· sites, cells from parasitized trap nests, and parasitized cells (Table 7). Although sample sizes were relatively small these data show that parasit· ism of P. cupidatus cells by O. aeneus results in increased cell length in trap· nests with bore diameters equal to or less than 4.8 mm. The t(II) test for differences in mean cell lengths between trap·nests without parasites and trap-nests with parasites was significant for 3.2 mm trap-nests (t = 2.343, df = 77, P < .025) and for 4.8 mm trap-nests (t 2.5563, df= 45, P < .005). Parasitized cells from 3.2, 4.0, and 4.8 mm bores had cell lengths which were respectively 51%, 26%, and 31  lo ger than cells from nonparasitized trap­nests. In a single 6,4 mm bore trap-nest, parasitism did not result in increased cell lengths. Passaloecus cuspidatus does not maximally use trap-nest bore volume. Larger bore diameter trap-nests contained cells with decreased length, while cells parasitized by Omalus aenus were longer than non-parasitized cells. Vol­ume of provisioned cells increased with increased bore diameter, but number of aphids provisioned did not increase proportionately with increased cell volume. Additionally, wasp senescence did not result in increased length of provisioned cells. LITERATURE CITED Danks, J. V. 1971. Biology of some stem-n sting aculeate Hymenoptera. Trans. Roy. Entomol. Soc. London. 122:323-399. Fricke, J. M. 1991. Trap-nest bore diameter preferences among sympatric Passaloecus spp. (Hymenoptera: Sphecidae). Great Lakes Entomol. 24:123-125. Fye, R. E. 1965. The biology of the Vespidae. Pompilidae and Sphecidae from trapn sts in northwestern Ontario. Canadian Entomol. 97:716-744. 7Fricke: Factors Influencing Length and Volume of Cells Provisioned by TwoPublished by ValpoScholar, 1992114 THE GREAT LAKES ENTOMOLOGIST Vol. 25, No.2 Krombein, K. V. 1967. Trap-nesting wasps and bees: Life histories, nests, and asso­ciates.Smithsonian Press, Washington D.C. vi + 570 pp. Vincent, D. L. 1978. A revision of the genus Passaloecus (Hymenoptera: Sphecidae; in America north of Mexico. Wasmann J. BioI. 36:127-198. 8The Great Lakes Entomologist, Vol. 25, No. 2 [1992], Art. 8https://scholar.valpo.edu/tgle/vol25/iss2/8

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Factors Influencing Length and Volume of Cells Provisioned by Two \u3ci\u3ePassaloecus\u3c/i\u3e Species (Hymemoptera: Sphecidae)

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