In a nondiapause culture of cereal leaf beetles, Oulema melanopus (Coleoptera: Chrysomelidae), females ovipositing within 20 days after emergence were considered nondiapause. However, sexually active males in the same generation could be nondiapause or prediapause. Changes in the nondiapause incidence were compared between progenies from\u3e 15 day old males that were feeding actively and photopositive (considered \u27nondiapause\u27 males) and progenies from younger males (nonselected males). Nondiapause females increased by 19% (n = 35 generations) and decreased 22% (n 31 generations) in the progenies of \u27nondiapause\u27 and nonselected males, respectively, suggesting that nondiapause males were selected in the former group, but prediapause males in the latter group substantially decreased nondiapause. In one generation, 14 progenies from individual pairs ranged from 21 to 100% nondiapause females, indicating that each sex in each parental pair was nondiapause, but nondiapause was incompletely expressed in most of the progenies.
The percentage of \u27nondiapause\u27 males was not significantly different than, and was strongly correlated to the percentage of nondiapause females of the same generation, indicating that nondiapause was not sex-linked, and that selecting males by age and behavior decreased the probability of dilution of nondiapause by prediapause males

Hoxie, R. P

Wellso, S. G

English

Valparaiso University

The Great Lakes Entomologist Volume 22 Number 3 - Fall 1989 Number 3 - Fall 1989 Article 5 October 1989 Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Males by Age and Feeding Behavior on Nondiapause Progeny S. G. Wellso Purdue University R. P. Hoxie Purdue University Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Wellso, S. G. and Hoxie, R. P. 1989. "Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Males by Age and Feeding Behavior on Nondiapause Progeny," The Great Lakes Entomologist, vol 22 (3) Available at: https://scholar.valpo.edu/tgle/vol22/iss3/5 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. 1989 THE GREAT LAKES ENTOMOLOGIST 133 EFFECT OF SELECTING CEREAL LEAF BEETLE (COLEOPTERA:CHRYSOMELIDAE) MALES BY AGE AND FEEDING BEHAVIOR ON NONDIAPAUSE PROGENY S. G. Well so and R. P. Hoxiel ABSTRACT In a nondiapause culture of cereal leaf beetles, Oul ma melanopus (Coleoptera: Chrysomelidae), females ovipositing within 20 days after emergence were considered nondiapause. However, sexually active males in the same generation could be nondia­pause or prediapause. Changes in the nondiapause incidence were compared between progenies from> 15 day old males that were feeding actively and photopositive (considered 'nondiapause' males) and progenies from younger males (nonselected males). Nondiapause females increased by 19% (n = 35 generations) and decreased 22% (n 31 generations) in the progenies of 'nondiapause' and nonselected males, respectively, suggesting that nondiapause males were selected in the former group, but prediapause males in the latter group substantially decreased nondiapause. In one generation, 14 progenies from individual pairs ranged from 21 to 100% nondiapause females, indicating that each sex in each parental pair was nondiapause, but nondiapause was incompletely expressed in most of the progenies. The percentage of 'nondiapause' males was not significantly different than, and was strongly correlated to the percentage of nondiapause females of the same generation, indicating that nondiapause was not sex-linked, and that selecting males by age and behavior decreased the probability of dilution of nondiapause by prediapause males. Cereal leaf beetles (CLB), Oulema melanopus (L.), are univoltine with an obligatory diapause (Hilterhaus 1965, Wellso 1974). In midwestern U.S., CLB emerge in late June through early July, and feed for about 3 weeks before dispersing to diapause sites for overwintering. In the spring, the beetles mate and oviposit. However, in Great Britain mating adults, eggs, and larvae have been observed in late summer prior to hibernation (diapause), suggesting the presence of a second generation (Hodson 1929). Wellso and Hoxie (1981) reported that a nondiapause strain of CLB was selected and maintained at 26.7°C from females that initiated oviposition ca. 8 days after emergence. Although diapause CLB were present at greatly varying proportions in most generations, 4 of 29 nondiapause generations had 100% nondiapause females. However, diapause females were present in the progenies of these 4 generations, suggesting that in the parental generations, there was either an incomplete transfer of the nondiapause trait or prediapause males had mated successfully. Diapause of males, occurring ca. 13 days after emergence, was usually preceded by 2 days of decreased feeding in conjunction with a photonegative behavior. Prediapause males fed significantly more than nondiapause IUSDA-Agricultural Research Service. Purdue University, West Lafayette, Indiana 47907. 1Wellso and Hoxie: Effect of Selecting Cereal Leaf Beetle (Coleoptera: ChrysomelidaePublished by ValpoScholar, 1989134 THE GREAT LAKES ENTOMOLOGIST Vol. 22, No.3 males during the first 8 days after emergence, indicating that nondiapause was genetically predetermined. Because prediapause or nondiapause males were incapable of fertilizing females earlier than 13 days after emergence, an asynchrony within a generation occasionally occurred between the periods of oviposition and sexual activity of males. Studies of nondiapause adult insects usually focus on females because oviposition is easier to quantify as a nondiapause trait than mating behavior of males. This study was conducted to ascertain if age and behavior were reliable traits for selecting nondiapause males. MATERIALS AND METHODS Nondiapause cereal leaf beetles were derived from a nondiapause culture (Wellso and Hoxie 1981), and 66 generations were reared by a method similar to that used for diapause CLB (Hoxie and Wellso 1983). These generations were from the main culture (37 generations) and two cultures derived from the main culture (12 and 7 generations). CLB were maintained in growth chambers at 26.7 1°C, 70 ± 10% R.H. and L16:D8. Within each generation, each CLB was sexed upon emergence, and placed in a screen tube containing 2-3 barley seedlings. Daily feeding for up to 20 days was rated as: 0 (no feeding), 1 (few leaf punctures), 2 (light feeding), and 3 (heavy feeding). Beetles not feeding for two consecutive days (in diapause) or females (usually 0-1% of the active females) that did not oviposit during the feeding-monitoring period were removed from the nondiapause culture. After oviposition was initiated, each female was transferred to a screened pot of barley for egg deposition, and males were subsequently placed in the oviposition cage. Each cage contained up to 20 females, and plants were changed every 3 days. One of two male selection methods for transferring males to the oviposition cage was assigned for each generation: (1) > IS day old males that for 2 days prior to seleetion were not photo­negative or feeding at a rating less than 2 (hereafter referred to as 'nondiapause' males) or (2) nonselected younger males. Although the assignation of the selection method to a generation was generally random, other conditions also influenced the assignment; e.g., if the CLB numbers were small and the parental nondiapause percentage was low, selecting for 'nondiapause' males was done to avoid losing the culture; emerged beetles in most generations were divided between this and other nondiapause studies (e.g., cross-breeding, L:D, field, or temperature) and the nonselected male method was commonly used; and, lastly, the three cultures were at times reared concurrently. Within each of the two male selection groups, the numbers of each sex in the parent and progeny generations that were diapause or nondiapause during the trial period were recorded (those that died were excluded from the totals). The percentage of nondiapause beetles in each generation was derived from the ratio of individuals estimated to be nondiapause (ovipositing females or selected males) to individuals that survived the test period. This percentage was subtracted from that o  the corresponding parent generation to show whether male selection changed the nondiapause percentages and in what direction. Means were compared between male selection groups by a Student's t-test. In the progenies of 18 selected and 14 nonselected male groups, the female nondiapause percentages and changes were compared to that of 'nondiapause' males of the same generation (Pearson correlations and paired t-tests). All statistical tests were performed using the Statistical Package for the Social Sciences (Nie et at. 1975). To investigate the male's transfer of nondiapause, 24 of 102 males from one of the generations were randomly designated upon emergence to either (1) selected 18-21 day old males with the same 'nondiapause' behaviorial criteria as previously defined (n = 12), or (2) 7-10 day old nonselected males (n = 12). Each male was paired with a nondiapause ovipositing virgin female from the same generation, and each pair was maintained in a screened tube containing barley plants. The percentage of cages with fertile eggs reflected the percentage of males (pre- or nondiapause) that successfully 2The Great Lakes Entomologist, Vol. 22, No. 3 [1989], Art. 5https://scholar.valpo.edu/tgle/vol22/iss3/51989 THE GREAT LAKES ENTOMOLOGIST 135 Table I.-Selection of cereal leaf beetle parental males by behavior: effect on nondiapause in their progeny. Mean values per generation Parental male selection" Nondiapause None Selection method CLB types Parent Progenyb change Parent change difference' J!'emales Diapause (no.) 12.1 6.9* - 5.1 4.3 11.4** + 7.1 - 4.4 Nondiapause (no.) 13.6 16.2ns + 2.6 13.2 II.4ns 1.8 + 4.8 Live (no.)d 25.7 23.ln5 + 2.5 17,5 22.8ns + 5.3 - 0.3 Nondiapause (9'<:) 57.3 76.6** + 19.3 74.3 51.9** - 22.4 + 24.7** Generations 35 31 Males Diapause (no.) 5.7 2.6n5 3.2 3.4 4.6n5 + 1.2 2.0 Nondiapause (no.) 13.3 12,2n8 + 1.1 16.6 12,3ns 4.3 0,\ Live (no,) 19,1 14.8ns 4.3 19.9 16.9n5 3.1 - 2.  Nondiapause (9'<:) 75.1 84,3* + 9.2 83.9 70.9** 13.0 + 13.4* Generations 18 14 *, P < 0.05; **, P < 0.00 I; ns, not significant (p > 0,05). a Males placed with nondiapause females: Nondiapause, males 15 days old and actively feeding 2 days prior to selection; None, males < 15 days old. bSignificance of a difference between generations (Paired Student's t-test) within each parental male group. 'Significance of a difference between parental male group progeny means (Student's t-test). d(Total emerged) - (total dead during the trial period). mated and was compared to the nondiapause percentage of females of the same generation that emerged within 1-2 days of the selected males. The percentage of nondiapause females in each pair's progeny was recorded t  indicate whether nondiapause was transferred from the parental male and whether the expression of nondiapause was 100%. RESULTS AND DISCUSSION The method of selecting parental males for placement with nondiapause females significantly affected the percentages of nondiapause females and the number of diapause females in their respective progenies (Table I). In the 35 progenies of selected males, there was a 19.3'7c increase in nondiapause females which reflected the decrease of 5,\ diapause females per generation, In the 31 progenies of nonselected males, there wa  a 22.4% decrease in nondiapause females and an increase of 7.1 diapause females per generation, suggesting that both pre- and nondiapause parental males were involved in mating. These nondiapause changes were also observed in the progeny males, i.e" the percentage of 'nondiapause' males in the progeny of selected and nonselected males, increased 9,2% and decreased 13,0%, respectively, There was no significant sexual difference between the number of diapause or nondiapause beetles, the percentage of nondiapause beetles, or the average nondiapause change (Table 2; paired t-tests, P > 0,05, n = 32 generations), However, for each variable, the correlation was significant (Pearson correlation, P < 0.001), This infers that, 3Wellso and Hoxie: Effect of Selecting Cereal Leaf Beetle (Coleoptera: ChrysomelidaePublished by ValpoScholar, 1989136 THE GREAT LAKES ENTOMOLOGIST Vol. 22, No.3 Table 2.--Comparisons of cereal leaf beetle males to females within each of 32 generations". Mean values per generation CLB status Females x 1: S.E. Males x 1: S.E. r-value b Diapause (no.) Nondiapause (no.) Live (no.)" Nondiapause (%) Nondiapause change (%) 3.63 0.49 13.69 ::':: 1.75 17.31 2.08 77.81 2.86 -0.  2.96 3.44 ::':: 0.53 12.25 ::':: 1.27 15.69 ::':: 1.62 78.42 ::':: 2.72 -0.50::':: 2.97 0.735 0.738 0.695 0.938 0.929 a18 selected and 14 nonselected male progenies. bAll Pearson Correlation r-values significant 0.001); no significant difference between female and male means (Paired Student's t-test. P 0.05). "(Total emerged) - (total dead during the trial period). 10~----""----------------"""""""""'-----------"'~-- ~--------------~~ (f) W ...J a: :r: w (f) ::J a: c... a: 	 /' / / / o /z o 	 'I> / / Z 	 /' / /I­Z /W /' /U /oc: W 	 '1>/0... 	 /' /' /' /' / //' / / ./ / 20 40 PERCENT NONJIRPAUSE FEMALES Figure I. Relationship of cereal leaf beetle 'nondiapause' males to nondiapause females in the same generation (Y = 4.18 + 0.95X; n 45, r2 0.95, P = 0.001) with 95% CL if the nondiapause trait is transferred by the male and female on a 1: 1 basis, the IJIOl' '-"'U,"'~IO of selected males in a generation would bc a close estimation of the percentagc nondiapause males (Figure I). When males from one nondiapause generation were paired with nondiapause females, 100% (12 of 12) and 42% (5 of 12) of the males in the selected and nonselected males, respectively, inseminated the females Crable 3). The percentage of sexually active males in the nonselected group, approximated the percentage of nondiapause females (48%, 31 4The Great Lakes Entomologist, Vol. 22, No. 3 [1989], Art. 5https://scholar.valpo.edu/tgle/vol22/iss3/51989 THE GREAT LAKES ENTOMOLOGIST 137 Table 3.-Perccnt of cereal leaf beetle f males that are nondiapause in each progeny of selected pairs. Selection of parental males for pairing with nondiapause femal s nondiapausea (18-21 days old) no selection (7-10 days old) Progeny females Progeny females Parent pairb Fertile parents live nondiapause Fertile parents liveC nondiapause (no.) (no.) (no.) (no.) (%) (no.) (no.) (no.) %) 1 14 7 50.0 0 2 16 7 43.8 0 3 7 5 71.4 0 4 30 18 60.0 0 5 0 I 15 8 53.3 6 21 18 85.7 0 7 0 0 8 14 9 64.3 0 9 I I 100.0 I 3 3 100.0 10 1 10 4 40.0 0 11 I 14 3 21.4 I 6 4 66.7 12 I 3 I 33.3 I 7 5 71.4 Totals 12 130 73 5 31 20 Progeny mean 13.0 7.3 57.0 7.8 5.0 72.9 ± S.D. 8.5 6.2 24.2 5.1 2.2 19.7 Parental sourced 15 32 46.9 16 32 50.0 aMales actively feeding and photopositive for 2 day  prior to pairing. bMales were randomly assigned to each male group pair as they emerged. C(Total emerged) -(tota! dead du ing the trial period); zero values indicate eggs and larvae, bnt no adult emergence.  dFemales from the same generation source as the selected pairs. of 64 females) from the same generation. Of the 17 pairs with fertile eggs, 14 progenies survived to the adult stage. Ovipositing (nondiapause) females were present in every progeny, indicating that all parental males were nondiapause. However, the percentages of nondiapause females varied from 21 to 100% indicating that there was usually an incomplete transferrence of nondiapause. To summarize, a 1:1 s xu l transferrence of nondiapause is indicated by the nonsignificant differences between the percentage of nondiapause females and 'non­diapause' males in each generation. Although only nondiapause females were in­seminated in each of the 66 generations, rejection of sexually competitive prediapause males usually occurred when male selection criteria were based on age and behavior. This was inferred from the increases and decreases in percentages of nondiapause females and 'nondiapause' males in the progenies of selected and nonselected males, respectively. However, generations with 100% nondiapause females rarely occurred and the percent nondiapause of the offspring usually decreased. This was also observed in the offspring of parental males that were known to have passed the nondiapause trait, indicating an incomplete transferrence of nondiapause to the progeny. Table 4 sum­marizes the types of CLB males encountered in a nondiapause culture. While nondiapause in the field has been observed infrequently, multiple generations would be advantageous to the CLB in the subtropics where host and environmental c ditions are favorable most of the year. 5Wellso and Hoxie: Effect of Selecting Cereal Leaf Beetle (Coleoptera: ChrysomelidaePublished by ValpoScholar, 1989138 THE GREAT LAKES ENTOMOLOGIST Vol. 22, No.3 Table 4.-Types of cereal leaf beetle males present within 20 days after emergence in a ondiapause culture and their effect on nondiapause in the next generation. Males present in a nondiapause culture Diapause status age" Sexual activity Effect on nondiapause in the next generation Diapause Prediapause Nondiapause early late none 13 >15 >15 none active active none decrease increase, usually incomplete "Days after emergence. ACKNOWLEDGMENTS Michigan Agric. Exp. Stn. Journal Article 12329. Part of a cooperative project between USDA-Agriculture Research Service, and the Dept. of Entomology, Michigan State Univ., East Lansing, 48824. LITERATURE CITED Duncan. D. B. 1955. Multiple range and multiple F tests. Biometrics 11:1-42. Hilterhaus, V. 1965. Biologisch-okologische Untersuchungen an Blattkafern der Gattungen Lema und Gastroidea (Chrysomelidae, Coleoptera) (Ein Beitrag zur Agrarokologie). Z. angew. Zoo!. 52:257-295. Hodson, W. E. H. 1929. The bionomics of Lema melanopa L. (Criocerinae), in Great Britain. Bull. Entomo!' Res. 20:5-14. Hoxie, R. P., and S. G. Wellso 1983. Cereal leaf beetle, Oulema melanopus (L) (Coleoptera: Chrysomelidae), responses to time in cold storage. Environ. Entomo!' 12:1695-1701. Nie, N. H., D. H. Hull, J. C. Jenkins, K. Steinbrenner, and D. H. Bent 1975. Statistical package for the social sciences, 2nd ed. McGraw-Hill, New York. 675 pp. Wellso, S. G. 1974. Aestivation in relation to oviposition initiation in the cereal leaf beetle. In L. E. Scheving, F. Halberg & J. E. Pauly (Eds.), Chronobiology, p. 597-601. Wellso, S. G., and R. P. Hoxie 1981. Diapause and nondiapause behavior of the cereal leaf beetle. Entomo!' Exp. App!. 30:19-25. 6The Great Lakes Entomologist, Vol. 22, No. 3 [1989], Art. 5https://scholar.valpo.edu/tgle/vol22/iss3/5

Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Males by Age and Feeding Behavior on Nondiapause Progeny

ValpoScholar

The Great Lakes Entomologist 
Volume 22 
Number 3 - Fall 1989 Number 3 - Fall 1989 Article 5 
October 1989 
Effect of Selecting Cereal Leaf Beetle (Coleoptera: 
Chrysomelidae) Males by Age and Feeding Behavior on 
Nondiapause Progeny 
S. G. Wellso 
Purdue University 
R. P. Hoxie 
Purdue University 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Wellso, S. G. and Hoxie, R. P. 1989. "Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae) 
Males by Age and Feeding Behavior on Nondiapause Progeny," The Great Lakes Entomologist, vol 22 (3) 
Available at: https://scholar.valpo.edu/tgle/vol22/iss3/5 
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. 
1989 THE GREAT LAKES ENTOMOLOGIST 133 
EFFECT OF SELECTING CEREAL LEAF BEETLE 
(COLEOPTERA:CHRYSOMELIDAE) MALES BY AGE AND 
FEEDING BEHAVIOR ON NONDIAPAUSE PROGENY 
S. G. Well so and R. P. Hoxiel 
ABSTRACT 
In 
a nondiapause culture 
of cereal leaf beetles, Oul ma melanopus (Coleoptera: 
Chrysomelidae), females ovipositing within 20 days after emergence were considered 
nondiapause. However, sexually active males in the same generation could be nondia­
pause or prediapause. Changes in the nondiapause incidence were compared between 
progenies from> 15 day old males that were feeding actively and photopositive 
(considered 'nondiapause' males) and progenies from younger males (nonselected males). 
Nondiapause females increased by 19% (n = 35 generations) and decreased 22% (n 
31 
generations) 
in the progenies of 'nondiapause' and nonselected males, respectively, 
suggesting that nondiapause males were selected in the former group, but prediapause 
males in the latter group substantially decreased nondiapause. In one generation, 14 
progenies from individual pairs ranged from 21 to 100% nondiapause females, indicating 
that each sex in each parental pair was nondiapause, but nondiapause was incompletely 
expressed in most of the progenies. 
The percentage of 'nondiapause' males was not significantly different than, and was 
strongly correlated to the percentage of nondiapause females of the same generation, 
indicating that nondiapause was not sex-linked, and that selecting males by age and 
behavior decreased the probability of dilution of nondiapause by prediapause males. 
Cereal leaf beetles (CLB), Oulema melanopus (L.), are univoltine with an obligatory 
diapause (Hilterhaus 1965, Wellso 1974). In midwestern U.S., CLB emerge in late June 
through early July, and feed for about 3 weeks before dispersing to diapause sites for 
overwintering. In the spring, the beetles mate and oviposit. However, in Great Britain 
mating adults, eggs, and larvae have been observed in late summer prior to hibernation 
(diapause), suggesting the presence of a second generation (Hodson 1929). 
Wellso and Hoxie (1981) reported that a nondiapause strain of CLB was selected and 
maintained at 26.7°C from females that initiated oviposition ca. 8 days after emergence. 
Although diapause CLB were present at greatly varying proportions in most generations, 
4 of 29 nondiapause generations had 100% nondiapause females. However, diapause 
females were present in the progenies of these 4 generations, suggesting that in the 
parental generations, there was either an incomplete transfer of the nondiapause trait or 
prediapause males had mated successfully. Diapause of males, occurring ca. 13 days after 
emergence, was usually preceded by 2 days of decreased feeding in conjunction with a 
photonegative behavior. Prediapause males fed significantly more than nondiapause 
IUSDA-Agricultural Research Service. Purdue University, West Lafayette, Indiana 47907. 
1
Wellso and Hoxie: Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae
Published by ValpoScholar, 1989
134 THE GREAT LAKES ENTOMOLOGIST Vol. 22, No.3 
males during the first 8 days after emergence, indicating that nondiapause was genetically 
predetermined. Because prediapause or nondiapause males were incapable of fertilizing 
females earlier than 13 days after emergence, an asynchrony within a generation 
occasionally occurred between the periods of oviposition and sexual activity of males. 
Studies of nondiapause adult insects usually focus on females because oviposition is 
easier to quantify as a nondiapause trait than mating behavior of males. This study was 
conducted to ascertain if age and behavior were reliable traits for selecting nondiapause 
males. 
MATERIALS AND METHODS 
Nondiapause cereal leaf beetles were derived from a nondiapause culture (Wellso and 
Hoxie 1981), and 66 generations were reared by a method similar to that used for diapause 
CLB (Hoxie and Wellso 1983). These generations were from the main culture (37 
generations) and two cultures derived from the main culture (12 and 7 generations). CLB 
were maintained in growth chambers at 26.7 1°C, 70 ± 10% R.H. and L16:D8. Within 
each generation, each CLB was sexed upon emergence, and placed in a screen tube 
containing 2-3 barley seedlings. Daily feeding for up to 20 days was rated as: 0 (no 
feeding), 1 (few leaf punctures), 2 (light feeding), and 3 (heavy feeding). Beetles not 
feeding for two consecutive days (in diapause) or females (usually 0-1% of the active 
females) that did not oviposit during the feeding-monitoring period were removed from 
the nondiapause culture. 
After oviposition was initiated, each female was transferred to a screened pot of barley 
for egg deposition, and males were subsequently placed in the oviposition cage. Each 
cage contained up to 20 females, and plants were changed every 3 days. One of two male 
selection methods for transferring males to the oviposition cage was assigned for each 
generation: (1) > IS day old males that for 2 days prior to seleetion were not photo­
negative or feeding at a rating less than 2 (hereafter referred to as 'nondiapause' males) 
or (2) nonselected younger males. Although the assignation of the selection method to a 
generation was generally random, other conditions also influenced the assignment; e.g., 
if 
the CLB numbers were small and the parental nondiapause percentage was low, 
selecting for 'nondiapause' males was done 
to avoid losing the culture; emerged beetles 
in 
most generations were divided between this and other nondiapause studies (e.g., 
cross-breeding, L:D, field, or temperature) and the nonselected male method was 
commonly used; and, lastly, 
the three cultures were at times reared concurrently. 
Within each of the two male selection groups, the numbers of each sex in the parent and 
progeny generations that were diapause or nondiapause during the trial period were 
recorded (those that died were excluded from the totals). The percentage of nondiapause 
beetles in each generation was derived from the ratio of individuals estimated to be 
nondiapause (ovipositing females or selected males) to individuals that survived the test 
period. This percentage was subtracted from that o  the corresponding parent generation 
to 
show whether male selection changed the nondiapause percentages and in what 
direction. Means were compared between male selection groups by a Student's t-test. In 
the progenies of 18 selected and 14 nonselected male groups, the female nondiapause percentages and changes were compared to that of 'nondiapause' males of the same 
generation (Pearson correlations and paired t-tests). All statistical tests were performed 
using the Statistical Package for the Social Sciences (Nie et at. 1975). 
To investigate the male's transfer of nondiapause, 24 of 102 males from one of the 
generations were randomly designated upon emergence to either (1) selected 18-21 day 
old males with the same 'nondiapause' behaviorial criteria as previously defined (n = 
12), or (2) 7-10 day old nonselected males (n = 12). Each male was paired with a 
nondiapause ovipositing virgin female from the same generation, and each pair was 
maintained in a screened tube containing barley plants. The percentage of cages with 
fertile eggs reflected the percentage of males (pre- or nondiapause) that successfully 
2
The Great Lakes Entomologist, Vol. 22, No. 3 [1989], Art. 5
https://scholar.valpo.edu/tgle/vol22/iss3/5
1989 THE GREAT LAKES ENTOMOLOGIST 135 
Table I.-Selection of cereal leaf beetle parental males by behavior: effect on nondiapause in 
their progeny. 
Mean values per generation 
Parental male selection" 
Nondiapause None 
Selection 
method 
CLB types Parent Progenyb change Parent change difference' 
J!'emales 
Diapause (no.) 
12.1 6.9* - 5.1 4.3 11.4** + 7.1 - 4.4 
Nondiapause (no.) 13.6 16.2ns + 2.6 13.2 II.4ns 1.8 + 4.8 
Live (no.)d 25.7 23.ln5 + 2.5 17,5 22.8ns + 5.3 - 0.3 
Nondiapause (9'<:) 57.3 76.6** + 19.3 74.3 51.9** - 22.4 + 24.7** 
Generations 35 31 
Males 
Diapause (no.) 5.7 2.6n5 3.2 3.4 4.6n5 + 1.2 2.0 
Nondiapause (no.) 13.3 12,2n8 + 1.1 16.6 12,3ns 4.3 0,\ 
Live (no,) 19,1 14.8ns 4.3 19.9 16.9n5 3.1 - 2.  
Nondiapause (9'<:) 75.1 84,3* + 9.2 83.9 70.9** 13.0 + 13.4* 
Generations 18 14 
*, P < 0.05; **, P < 0.00 I; ns, not significant (p > 0,05). 

a Males placed with nondiapause females: Nondiapause, males 15 days old and actively feeding 

2 days prior to selection; None, males < 15 days old. 

bSignificance of a difference between generations (Paired Student's t-test) within each parental male 

group. 

'Significance of a difference between parental male group progeny means (Student's t-test). 

d(Total emerged) - (total dead during the trial period). 

mated and was compared to the nondiapause percentage of females of the same generation 
that emerged within 1-2 days of the selected males. The percentage of nondiapause 
females in each pair's progeny was recorded t  indicate whether nondiapause was 
transferred from the parental male and whether the expression of nondiapause was 100%. 
RESULTS AND DISCUSSION 
The method of selecting parental males for placement with nondiapause females 
significantly affected the percentages of nondiapause females and the number of diapause 
females in their respective progenies (Table I). In the 35 progenies of selected males, 
there was a 19.3'7c increase in nondiapause females which reflected the decrease of 5,\ 
diapause females per generation, In the 31 progenies of nonselected males, there wa  a 
22.4% decrease in nondiapause females and an increase of 7.1 diapause females per 
generation, suggesting that both pre- and nondiapause parental males were involved in 
mating. These nondiapause changes were also observed in the progeny males, i.e" the 
percentage of 'nondiapause' males in the progeny of selected and nonselected males, 
increased 9,2% and decreased 13,0%, respectively, 
There was no significant sexual difference between the number of diapause or 
nondiapause beetles, the percentage of nondiapause beetles, or the average nondiapause 
change (Table 2; paired t-tests, P > 0,05, n = 32 generations), However, for each 
variable, the correlation was significant (Pearson correlation, P < 0.001), This infers that, 
3
Wellso and Hoxie: Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae
Published by ValpoScholar, 1989
136 THE GREAT LAKES ENTOMOLOGIST Vol. 22, No.3 
Table 2.--Comparisons of cereal leaf beetle males to females within each of 32 generations". 
Mean values per generation 
CLB status 
Females 
x 1: S.E. 
Males 
x 1: S.E. r-value b 
Diapause (no.) 
Nondiapause (no.) 
Live (no.)" 
Nondiapause (%) 
Nondiapause change (%) 
3.63 0.49 
13.69 ::':: 1.75 
17.31 
2.08 
77.81 2.86 -0.  
2.96 
3.44 
::':: 0.53 
12.25 ::':: 1.27 
15.69 ::':: 1.62 
78.42 ::':: 2.72 
-0.50::':: 2.97 
0.735 
0.738 
0.695 
0.938 
0.929 
a18 
selected and 
14 nonselected male progenies. 

bAll Pearson Correlation r-values significant 0.001); no significant difference between female 

and male means (Paired Student's t-test. P 0.05). 

"(Total emerged) - (total dead during the trial period). 

10~----""----------------"""""""""'-----------"'~-- ~--------------~~ 
(f) 
W 

...J 

a: 
:r: 
w 
(f) 
::J 
a: 
c... 
a: 	 /' / 
/ / 
o /z 
o 	 'I> / / 
Z 	 /' / 

/
I­
Z /W /' /U /
oc: 
W 	 '1>/
0... 	 /' 
/' /' 
/' / 
/
/' 
/ 
/ 
./ 
/ 
20 40 
PERCENT NONJIRPAUSE FEMALES 
Figure I. Relationship of cereal leaf beetle 'nondiapause' males to nondiapause females in the same 
generation (Y = 4.18 + 0.95X; n 45, r2 0.95, P = 0.001) with 95% CL 
if the nondiapause trait is transferred by the male and female on a 1: 1 basis, the IJIOl' '-"'U,"'~IO 
of selected males in a generation would bc a close estimation of the percentagc 
nondiapause males (Figure I). 
When males from one nondiapause generation were paired with nondiapause females, 
100% (12 of 12) and 42% (5 of 12) of the males in the selected and nonselected males, 
respectively, inseminated the females Crable 3). The percentage of sexually active males 
in the nonselected group, approximated the percentage of nondiapause females (48%, 31 
4
The Great Lakes Entomologist, Vol. 22, No. 3 [1989], Art. 5
https://scholar.valpo.edu/tgle/vol22/iss3/5
1989 THE GREAT LAKES ENTOMOLOGIST 137 
Table 3.-Perccnt of cereal leaf beetle f males that are nondiapause in each progeny of 
selected pairs. 
Selection of parental males for pairing with nondiapause femal s 
nondiapausea (18-21 days old) no selection (7-10 days old) 
Progeny females Progeny females 
Parent pairb Fertile parents live nondiapause Fertile parents live
C 
nondiapause 
(no.) (no.) (no.) (no.) (%) (no.) (no.) (no.) %) 
1 14 7 50.0 0 
2 16 7 43.8 0 
3 7 5 71.4 0 
4 30 18 60.0 0 
5 0 I 15 8 53.3 
6 21 18 85.7 0 
7 0 0 
8 14 9 64.3 0 
9 I I 100.0 I 3 3 100.0 
10 
1 
10 4 40.0 0 
11 I 14 3 21.4 I 6 4 66.7 
12 I 3 I 33.3 I 7 5 71.4 
Totals 12 130 73 5 31 20 
Progeny mean 
13.0 7.3 57.0 7.8 
5.0 72.9 
± S.D. 8.5 6.2 24.2 5.1 2.2 19.7 
Parental sourced 15 
32 46.9 16 32 50.0 
aMales actively feeding and photopositive for 2 day  prior to pairing. 

bMales were randomly assigned to each male group 
pair 
as they emerged. 

C(Total emerged) 
-
(tota! dead du ing the trial period); zero values indicate eggs and larvae, bnt no 

adult 
emergence. 
 dFemales from the same generation source as the 
selected pairs. 

of 
64 females) from the same generation. 
Of the 17 pairs with fertile eggs, 14 progenies 
survived to the adult stage. Ovipositing (nondiapause) females were present in every 
progeny, indicating that all parental males were nondiapause. However, the percentages 
of 
nondiapause females varied from 
21 to 100% indicating that there was usually an 
incomplete transferrence of nondiapause. 
To summarize, a 1:1 s xu l transferrence of nondiapause is indicated by the 
nonsignificant differences between the percentage of nondiapause females and 'non­
diapause' males in each generation. Although only nondiapause females were in­
seminated in each of the 66 generations, rejection of sexually competitive prediapause 
males usually occurred when male selection criteria were based on age and behavior. 
This was inferred from the increases and decreases in percentages of nondiapause 
females and 'nondiapause' males in the progenies of selected and nonselected males, 
respectively. However, generations with 100% nondiapause females rarely occurred and 
the percent nondiapause of the offspring usually decreased. This was also observed in the 
offspring of parental males that were known to have passed the nondiapause trait, 
indicating an incomplete transferrence of nondiapause to the progeny. Table 4 sum­
marizes the types of CLB males encountered in a nondiapause culture. While 
nondiapause in the field has been observed infrequently, multiple generations would be 
advantageous to the CLB in the subtropics where host and environmental c ditions are 
favorable most of the year. 
5
Wellso and Hoxie: Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae
Published by ValpoScholar, 1989
138 THE GREAT LAKES ENTOMOLOGIST Vol. 22, No.3 
Table 4.-Types of cereal leaf beetle males present within 20 days after emergence in a ondiapause 
culture and their effect on nondiapause in the next generation. 
Males present in a 
nondiapause culture 
Diapause 
status age" 
Sexual 
activity 
Effect on nondiapause 
in the next generation 
Diapause 
Prediapause 
Nondiapause 
early 
late 
none 
13 
>15 
>15 
none 
active 
active 
none 
decrease 
increase, usually incomplete 
"Days after emergence. 
ACKNOWLEDGMENTS 
Michigan Agric. Exp. Stn. Journal Article 12329. Part of a cooperative project between 
USDA-Agriculture Research Service, and the Dept. of Entomology, Michigan State 
Univ., East Lansing, 48824. 
LITERATURE CITED 
Duncan. D. B. 1955. Multiple range and multiple F tests. Biometrics 11:1-42. 
Hilterhaus, V. 1965. Biologisch-okologische Untersuchungen an Blattkafern der Gattungen Lema 
und Gastroidea (Chrysomelidae, Coleoptera) (Ein Beitrag zur Agrarokologie). Z. angew. Zoo!. 
52:257-295. 
Hodson, W. E. H. 1929. The bionomics of Lema melanopa L. (Criocerinae), in Great Britain. Bull. 
Entomo!' Res. 20:5-14. 
Hoxie, R. P., and S. G. Wellso 1983. Cereal leaf beetle, Oulema melanopus (L) (Coleoptera: 
Chrysomelidae), responses to time in cold storage. Environ. Entomo!' 12:1695-1701. 
Nie, N. H., D. H. Hull, J. C. Jenkins, K. Steinbrenner, and D. H. Bent 1975. Statistical package 
for the social sciences, 2nd ed. McGraw-Hill, New York. 675 pp. 
Wellso, S. G. 1974. Aestivation in relation to oviposition initiation in the cereal leaf beetle. In L. E. 
Scheving, F. Halberg & J. E. Pauly (Eds.), Chronobiology, p. 597-601. 
Wellso, S. G., and R. P. Hoxie 1981. Diapause and nondiapause behavior of the cereal leaf beetle. 
Entomo!' Exp. App!. 30:19-25. 
6
The Great Lakes Entomologist, Vol. 22, No. 3 [1989], Art. 5
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Effect of Selecting Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Males by Age and Feeding Behavior on Nondiapause Progeny

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