Lygaeus kalmii Stal (Hemiptera: Lygaeidae) is an insect found throughout the eastern United States and Canada. There is extensive taxonomic literature on this insect (Stil, 1874; Townsend, 1887; Parshey, 1919, 1923; Slater and Knopf, 1969), but very little attention has been given to the rest of its biology. This study describes the habits of kalmii populations in southern Michigan

Hunt, Linda-Margaret

English

Valparaiso University

The Great Lakes Entomologist Volume 12 Number 1 - Spring 1979 Number 1 - Spring 1979 Article 6 April 1979 Observations of the Habits of Lygaeus Kalmii Angustomarginatus (Hemiptera: Lygaeidae) in Southern Michigan Linda-Margaret Hunt University of Notre Dame Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Hunt, Linda-Margaret 1979. "Observations of the Habits of Lygaeus Kalmii Angustomarginatus (Hemiptera: Lygaeidae) in Southern Michigan," The Great Lakes Entomologist, vol 12 (1) Available at: https://scholar.valpo.edu/tgle/vol12/iss1/6 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. THE GREAT LAKES ENTOMOLOGIST OBSERVATIONS OF THE HABITS OF LYGAEUS KALMll ANGUSTOMARGINATUS (HEMIPTERA: LYGAEIDAE) IN SOUTHERN  MICHIGAN^ Linda-Margaret ~ u n t ~  Lygaeus kalmii St% (Hemiptera: Lygaeidae) is an insect found throughout the eastern United States and Canada. There is extensive taxonomic literature on this insect (Stil, 1874; Townsend, 1887; Parshey, 1919, 1923; Slater and Knopf, 1969), but very little attention has been given to the rest of its biology. This study describes the habits of kalmii populations in southern Michigan. Lygaeus kalmii angustomarginatus (Parshley) is the subspecies of kalmii common in the northeastern United States and southern Canada from the Atlantic Ocean to the 100th meridian. Its taxonomy was extensively reexamined by Slater and Knopf (1969). All observations described in this paper are based on populations of angustomarginatus, hereafter referred to as Lygaeus kalmii. While the sub-specific descriptions of this insect have caused much discussion among taxonomists, I have found that the common name is more often misinterpreted by casual observors. L. kalmii is known as the lesser milkweed bug. Despite the assumptions suggested by this trivial name, kalmii is not limited to AsClepias in its food plants in Livingston, Monroe, St. Joseph, and Washtenaw counties in Michigan. L. kalmii is a member of a variety of mid-succession communities. Verbascum thapsus L., Rhus typhina L., Carduus spp., and a variety of grasses and sedges are commonly present along with one to several species of Asclepias. Several species of annual angiosperms are also usually present. When kalmii feeds upon milkweed, it is most often Ascelpias syriaca L. Nonmilkweed species which have been observed to serve as food sources include Prunus ~rn0ldZkna Rehd. (Townsend, 1887), Ambrosia sp. (Townsend, 1887), Poa pratensis (Simanton and Andre, 19351, Rhlis sp., Helianthus sp., Phaseolus sp. and Eranthis hyernalis (L.), one of the earliest of spring flowers in southern Michigan. Unlike Oncopeltus fasciatus (Dallas), the greater milkweed bug, L. kalmii is not a migratory insect. It overwinters in its usual habitat in quiescent state, having no true diapause. Simanton and Andre (1935) asserted that only adults overwinter and that they do not begin reproduction until the following April. Caldwell (1969) concurred, although he found nymphs in James County, Iowa, as late as December and fertile females as early as 1 March. Laboratory studies by Caldwell and Dingle (1971) indicated that kalmii is sterile at temperatures below 25°C. Were this the case in nature, the breeding season would be limited to four to five months each year in Michigan populations and fertile adults should not be found in the other months. While this life history fits the 0 .  fasciatus populations found in southern Michigan, my observations indicated it is not accurate for the L. kalmii there. As shown in Table 1, adult kalmii can be found any time of year when the ground is not covered with dense vegetation (July) or snow (December). The collections made during the winter months were made on sunny days when the adults can be found basking. It was noted that females were receptive to males in all seasons, being found in coitu or establishing this relationship within two minutes after having been placed with a male (observations made in the field). When winter-collected animals were placed under I A  portion of this study was supported by Horace H. Rackham School of Graduate Studies block grants and was submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Zoology) in The University of Michigan. 2~epa r tmen t  of Biology, University of Notre Dame, Notre Dame, IN 46556. 1Hunt: Observations of the Habits of <i>Lygaeus Kalmii AngustomarginatusPublished by ValpoScholar, 197932 THE GREAT LAKES ENTOMOLOGIST Vol. 12, No. 1 Table 1. Seasonal life history data on Lygaeus kalmii gathered in 1975 at selected sites in southern Michigan. Number Observed/lO m1 Air Temp. Females First Date in "C Adults Nymphs Receptive Eggs yes yes laboratory conditions (20°C, 50% rel. hum.) with the natural photoperiod, they produced eggs within one week (Table 1). Newly emerged females reared at 25OC in the laboratory required a minimum five days to produce their first clutches (Hunt, 1975). These data suggest that the process of egg production is an on-going one, even during the winter months. Thus, although an ambient temperature below 25'C may retard egg production in the laboratory (Dingle and Caldwell, 1975), it does not block it completely in nature. This phenomenon may have one of several explanations. A brief exposure to the limiting temperature may be sufficient to complete the process, or the basking behavior of the adults may elevate their body temperatures above the ambient limiting temperature. While I have found nymphs only during the warm weather months, the following observations lead me to conclude that nymphs are probably present year round. First, most adults taken during the winter months have bright, unscratched, clean cuticles. Second, two individuals taken on 22 February were found not to have completed teneral cuticle deposition, which normally takes place during the first five days post-meta- morphosis in laboratory stocks reared at 25'C. Third, one individual taken on 13 April was in the process of cuticle tanning, which occurs immediately after metamorphosis. These three observations can best be explained by the assumption that all of these adults had very recently metamorphosed, having overwintered as nymphs. My laboratory obse~at ions  confirm that fifth instar nymphs can survive temperatures as low as 0°C for periods of up to two weeks and as low as 7°C for period of up to two months. Also, normal development from embryo to fifth instar can occur at 20°C although it requires two months to complete (Hunt, 1975). The adults and nymphs which leave their sub-surface hibernacula and become active during January through May have two major problems: where to find food and shelter. The solution to these is often the same, Verbascutn thapsus L., the mullein plant, which is often found in milkweed communities in southern Michigan. Its thick, fuzzy leaves serve as an insulator for many insects, and they are also excellent traps for milkweed seeds. Thus they provide insulation, protection, and food during the months before Asclepias breaks ground. Besides foraging for last year's milkweed seeds, kalmii feeds on other plant materials as they become available. Eranthis hyemalis blooms in mid-February in my collecting area. This is at a time when Asclepias seeds are difficult to find because of the snow cover which is usually present. In 1975, Thomas Friedlander and I observed adult kalmii systematically moving from nectary to nectary of this flower, stopping at each to feed and becoming coated with pollen in the process. This sort of opportunistic foraging 2The Great Lakes Entomologist, Vol. 12, No. 1 [1979], Art. 6https://scholar.valpo.edu/tgle/vol12/iss1/61979 THE GREAT LAKES ENTOMOLOGIST 3 3 behavior continues throughout the spring and summer months, kalmii switching from host to host as each flowgrs. Such reliance upon flowers was not anticipated, inasmuch as kalmii is usually thought of as a seed feeder. When feeding upon seeds, kalmii first saws a hole through the seed coat using its four rasp-like stylets. Salivary enzymes are secreted onto the endosperm, and the liquidified material is then pumped into the esophagus through the beak's long food channel (Newcomer, 1948). My observations indicate that other liquids (water, nectar, sap) are also pumped in this manner, thus expanding the food choices of kalmii considerably. It is not until late June that the insect becomes common on Asclepias spp. and it cannot be considered abundant there until July and August. During these months, kalmii feeds on both the fluids and the developing seeds of Asclepias. While adults are found on the upper foliage of plants as well as on the ground, the nymphal instars are most commonly restricted to either the ground or the lower shoots of plants. One exception is seen at the time of metamorphosis. At this time fifth instar nymphs leave the shelter of the ground cover and climb to the terminal buds of Asclepias. This behavior may have evolved as a protection from conspecifics. L. kalmii are usually phytophagous fluid-feeders. However, when the opportunity presents itself, cannibalism is not uncommon. Examples of opportunities include the presence of a freshly molted nymph or adult or a clutch of eggs. Within a clutch, nymphs develop synchronously until the fifth instar, but the onset of metamorphosis often varies as much as three days. While aposematic coloration works as a defense mechanism against other predators, it is ignored by conspecifics. Thus, the climbing behavior, only exhibited immediately to  metamorphosis, removes the possible prey from the vicinity of its siblings. CONCLUSIONS Lygaeus kalmii angustomarginatus is a multivoltine resident of mid-succession plant communities of southern Michigan. It is mainly phytophagous, feeding on the fluids and seeds of a variety of angiosperms. It gives preference to Asclepias spp. when they are available and forages for dormant seeds during the winter. Nymphs and adults of kalmii are probably present in all seasons. During the winter, adults and probably nymphs as well utilize sub-surface hibernacula and the protection of Verbascum for surviving periods of temperature-regulated quiescense. LITERATURE CITED Caldwell, R. L. 1969. A comparison of the dispersal strategies of two milkweed bugs, Oncopeltus fasciatus and Lygaeus kalmii. Ph.D. Thesis. Univ. Iowa. Dingle, H. and R. L. Caldwell. 1971. Temperature and reproductive success in Oncopeltus fasciatus, 0 .  unifasciatellus, Lygaeus kalmii, and L. turcicus. Ann. Entomol. Soc. Amer. 64: 1171-1172. Hunt, L.-M. 1975. Developmental biology of Lygaeus kalmii under natural and experi- mental conditions. Ph.D. Thesis. Univ. Mich. Newcomer, W. S. 1948. Embryological development of the mouth parts and related structures of the milkweed bug, Oncopeltus fasciatus (Dallas). J. Morph. 82:365-412. Parshley, H. M. 1919. On some Hemiptera from western Canada, Occas. Papers Mus. Zool. Univ. Mich. . 1923. The distribution and forms of Lygaeus kalmii St81 with remarks on insect zoogeography (Hemiptera, Lygaeidae). Canad. Entomol. 55:81-84. Simanton, W. A. and F. Andre. 1936. A biological study of Lygaeus kalmii St81 (Hemiptera-Lygaeidae). Bull. Brooklyn Entomol. Soc. 31:99-107. Slater, J. A. and N. F. Knopf. 1969. Geographic variation in the North American milkweed bugs of the Lygaeus kalmii complex. Ann. Entomol. Soc. Amer. 62:1221-1232. St%, C. 1874. Enumeratis Hemipterorum, pt. 4,  K. Svenska Vetensk. Akad. Handl. 12: 1-186. 3Hunt: Observations of the Habits of <i>Lygaeus Kalmii AngustomarginatusPublished by ValpoScholar, 1979

Observations of the Habits of \u3ci\u3eLygaeus Kalmii Angustomarginatus\u3c/i\u3e (Hemiptera: Lygaeidae) in Southern Michigan

ValpoScholar

The Great Lakes Entomologist 
Volume 12 
Number 1 - Spring 1979 Number 1 - Spring 1979 Article 6 
April 1979 
Observations of the Habits of Lygaeus Kalmii Angustomarginatus 
(Hemiptera: Lygaeidae) in Southern Michigan 
Linda-Margaret Hunt 
University of Notre Dame 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Hunt, Linda-Margaret 1979. "Observations of the Habits of Lygaeus Kalmii Angustomarginatus 
(Hemiptera: Lygaeidae) in Southern Michigan," The Great Lakes Entomologist, vol 12 (1) 
Available at: https://scholar.valpo.edu/tgle/vol12/iss1/6 
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. 
THE GREAT LAKES ENTOMOLOGIST 
OBSERVATIONS OF THE HABITS OF 
LYGAEUS KALMll ANGUSTOMARGINATUS 
(HEMIPTERA: LYGAEIDAE) IN SOUTHERN  MICHIGAN^ 
Linda-Margaret ~ u n t ~  
Lygaeus kalmii St% (Hemiptera: Lygaeidae) is an insect found throughout the eastern 
United States and Canada. There is extensive taxonomic literature on this insect (Stil, 
1874; Townsend, 1887; Parshey, 1919, 1923; Slater and Knopf, 1969), but very little 
attention has been given to the rest of its biology. This study describes the habits of 
kalmii populations in southern Michigan. 
Lygaeus kalmii angustomarginatus (Parshley) is the subspecies of kalmii common in 
the northeastern United States and southern Canada from the Atlantic Ocean to the 
100th meridian. Its taxonomy was extensively reexamined by Slater and Knopf (1969). 
All observations described in this paper are based on populations of angustomarginatus, 
hereafter referred to as Lygaeus kalmii. 
While the sub-specific descriptions of this insect have caused much discussion among 
taxonomists, I have found that the common name is more often misinterpreted by casual 
observors. L. kalmii is known as the lesser milkweed bug. Despite the assumptions 
suggested by this trivial name, kalmii is not limited to AsClepias in its food plants in 
Livingston, Monroe, St. Joseph, and Washtenaw counties in Michigan. 
L. kalmii is a member of a variety of mid-succession communities. Verbascum thapsus 
L., Rhus typhina L., Carduus spp., and a variety of grasses and sedges are commonly 
present along with one to several species of Asclepias. Several species of annual 
angiosperms are also usually present. 
When kalmii feeds upon milkweed, it is most often Ascelpias syriaca L. Nonmilkweed 
species which have been observed to serve as food sources include Prunus ~rn0ldZkna 
Rehd. (Townsend, 1887), Ambrosia sp. (Townsend, 1887), Poa pratensis (Simanton and 
Andre, 19351, Rhlis sp., Helianthus sp., Phaseolus sp. and Eranthis hyernalis (L.), one of 
the earliest of spring flowers in southern Michigan. 
Unlike Oncopeltus fasciatus (Dallas), the greater milkweed bug, L. kalmii is not a 
migratory insect. It overwinters in its usual habitat in quiescent state, having no true 
diapause. Simanton and Andre (1935) asserted that only adults overwinter and that they 
do not begin reproduction until the following April. Caldwell (1969) concurred, although 
he found nymphs in James County, Iowa, as late as December and fertile females as early 
as 1 March. Laboratory studies by Caldwell and Dingle (1971) indicated that kalmii is 
sterile at temperatures below 25°C. Were this the case in nature, the breeding season 
would be limited to four to five months each year in Michigan populations and fertile 
adults should not be found in the other months. While this life history fits the 0 .  
fasciatus populations found in southern Michigan, my observations indicated it is not 
accurate for the L. kalmii there. 
As shown in Table 1, adult kalmii can be found any time of year when the ground is 
not covered with dense vegetation (July) or snow (December). The collections made 
during the winter months were made on sunny days when the adults can be found 
basking. It was noted that females were receptive to males in all seasons, being found in 
coitu or establishing this relationship within two minutes after having been placed with a 
male (observations made in the field). When winter-collected animals were placed under 
I A  portion of this study was supported by Horace H. Rackham School of Graduate 
Studies block grants and was submitted in partial fulfillment of the requirements for the 
degree of Doctor of Philosophy (Zoology) in The University of Michigan. 
2~epa r tmen t  of Biology, University of Notre Dame, Notre Dame, IN 46556. 
1
Hunt: Observations of the Habits of <i>Lygaeus Kalmii Angustomarginatus
Published by ValpoScholar, 1979
32 THE GREAT LAKES ENTOMOLOGIST Vol. 12, No. 1 
Table 1. Seasonal life history data on Lygaeus kalmii gathered in 1975 at selected sites in 
southern Michigan. 
Number Observed/lO m1 
Air Temp. Females First 
Date in "C Adults Nymphs Receptive Eggs 
yes 
yes 
laboratory conditions (20°C, 50% rel. hum.) with the natural photoperiod, they produced 
eggs within one week (Table 1). Newly emerged females reared at 25OC in the laboratory 
required a minimum five days to produce their first clutches (Hunt, 1975). These data 
suggest that the process of egg production is an on-going one, even during the winter 
months. Thus, although an ambient temperature below 25'C may retard egg production 
in the laboratory (Dingle and Caldwell, 1975), it does not block it completely in nature. 
This phenomenon may have one of several explanations. A brief exposure to the limiting 
temperature may be sufficient to complete the process, or the basking behavior of the 
adults may elevate their body temperatures above the ambient limiting temperature. 
While I have found nymphs only during the warm weather months, the following 
observations lead me to conclude that nymphs are probably present year round. First, 
most adults taken during the winter months have bright, unscratched, clean cuticles. 
Second, two individuals taken on 22 February were found not to have completed teneral 
cuticle deposition, which normally takes place during the first five days post-meta- 
morphosis in laboratory stocks reared at 25'C. Third, one individual taken on 13 April 
was in the process of cuticle tanning, which occurs immediately after metamorphosis. 
These three observations can best be explained by the assumption that all of these adults 
had very recently metamorphosed, having overwintered as nymphs. My laboratory 
obse~at ions  confirm that fifth instar nymphs can survive temperatures as low as 0°C for 
periods of up to two weeks and as low as 7°C for period of up to two months. Also, 
normal development from embryo to fifth instar can occur at 20°C although it requires 
two months to complete (Hunt, 1975). 
The adults and nymphs which leave their sub-surface hibernacula and become active 
during January through May have two major problems: where to find food and shelter. 
The solution to these is often the same, Verbascutn thapsus L., the mullein plant, which 
is often found in milkweed communities in southern Michigan. Its thick, fuzzy leaves 
serve as an insulator for many insects, and they are also excellent traps for milkweed 
seeds. Thus they provide insulation, protection, and food during the months before 
Asclepias breaks ground. 
Besides foraging for last year's milkweed seeds, kalmii feeds on other plant materials 
as they become available. Eranthis hyemalis blooms in mid-February in my collecting 
area. This is at a time when Asclepias seeds are difficult to find because of the snow 
cover which is usually present. In 1975, Thomas Friedlander and I observed adult kalmii 
systematically moving from nectary to nectary of this flower, stopping at each to feed 
and becoming coated with pollen in the process. This sort of opportunistic foraging 
2
The Great Lakes Entomologist, Vol. 12, No. 1 [1979], Art. 6
https://scholar.valpo.edu/tgle/vol12/iss1/6
1979 THE GREAT LAKES ENTOMOLOGIST 3 3 
behavior continues throughout the spring and summer months, kalmii switching from 
host to host as each flowgrs. Such reliance upon flowers was not anticipated, inasmuch as 
kalmii is usually thought of as a seed feeder. When feeding upon seeds, kalmii first saws a 
hole through the seed coat using its four rasp-like stylets. Salivary enzymes are secreted 
onto the endosperm, and the liquidified material is then pumped into the esophagus 
through the beak's long food channel (Newcomer, 1948). My observations indicate that 
other liquids (water, nectar, sap) are also pumped in this manner, thus expanding the 
food choices of kalmii considerably. It is not until late June that the insect becomes 
common on Asclepias spp. and it cannot be considered abundant there until July and 
August. During these months, kalmii feeds on both the fluids and the developing seeds of 
Asclepias. 
While adults are found on the upper foliage of plants as well as on the ground, the 
nymphal instars are most commonly restricted to either the ground or the lower shoots 
of plants. One exception is seen at the time of metamorphosis. At this time fifth instar 
nymphs leave the shelter of the ground cover and climb to the terminal buds of 
Asclepias. This behavior may have evolved as a protection from conspecifics. L. kalmii are 
usually phytophagous fluid-feeders. However, when the opportunity presents itself, 
cannibalism is not uncommon. Examples of opportunities include the presence of a 
freshly molted nymph or adult or a clutch of eggs. Within a clutch, nymphs develop 
synchronously until the fifth instar, but the onset of metamorphosis often varies as much 
as three days. While aposematic coloration works as a defense mechanism against other 
predators, it is ignored by conspecifics. Thus, the climbing behavior, only exhibited 
immediately to  metamorphosis, removes the possible prey from the vicinity of its siblings. 
CONCLUSIONS 
Lygaeus kalmii angustomarginatus is a multivoltine resident of mid-succession plant 
communities of southern Michigan. It is mainly phytophagous, feeding on the fluids and 
seeds of a variety of angiosperms. It gives preference to Asclepias spp. when they are 
available and forages for dormant seeds during the winter. Nymphs and adults of kalmii 
are probably present in all seasons. During the winter, adults and probably nymphs as 
well utilize sub-surface hibernacula and the protection of Verbascum for surviving periods 
of temperature-regulated quiescense. 
LITERATURE CITED 
Caldwell, R. L. 1969. A comparison of the dispersal strategies of two milkweed bugs, 
Oncopeltus fasciatus and Lygaeus kalmii. Ph.D. Thesis. Univ. Iowa. 
Dingle, H. and R. L. Caldwell. 1971. Temperature and reproductive success in Oncopeltus 
fasciatus, 0 .  unifasciatellus, Lygaeus kalmii, and L. turcicus. Ann. Entomol. Soc. 
Amer. 64: 1171-1172. 
Hunt, L.-M. 1975. Developmental biology of Lygaeus kalmii under natural and experi- 
mental conditions. Ph.D. Thesis. Univ. Mich. 
Newcomer, W. S. 1948. Embryological development of the mouth parts and related 
structures of the milkweed bug, Oncopeltus fasciatus (Dallas). J. Morph. 82:365-412. 
Parshley, H. M. 1919. On some Hemiptera from western Canada, Occas. Papers Mus. 
Zool. Univ. Mich. 
. 1923. The distribution and forms of Lygaeus kalmii St81 with remarks on 
insect zoogeography (Hemiptera, Lygaeidae). Canad. Entomol. 55:81-84. 
Simanton, W. A. and F. Andre. 1936. A biological study of Lygaeus kalmii St81 
(Hemiptera-Lygaeidae). Bull. Brooklyn Entomol. Soc. 31:99-107. 
Slater, J. A. and N. F. Knopf. 1969. Geographic variation in the North American 
milkweed bugs of the Lygaeus kalmii complex. Ann. Entomol. Soc. Amer. 
62:1221-1232. 
St%, C. 1874. Enumeratis Hemipterorum, pt. 4,  K. Svenska Vetensk. Akad. Handl. 
12: 1-186. 
3
Hunt: Observations of the Habits of <i>Lygaeus Kalmii Angustomarginatus
Published by ValpoScholar, 1979


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Observations of the Habits of \u3ci\u3eLygaeus Kalmii Angustomarginatus\u3c/i\u3e (Hemiptera: Lygaeidae) in Southern Michigan

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