22 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY 1972. Coevolution: patterns of legume predation by a lycaenid butterfly. Oecologia, in press. BRUSSARD, P. F . & P. R. EHRLICH. 1970. Contrasting population biology of two species of butterflies. Nature 227: 91-92. DETmER, V. G. 1959. Food-plant distribution and density and larval dispersal as factors affecting insect populations. Can. Entomol. 91 : 581-596. DOWNEY, J. C. & W. C. FULLER. 1961. Variation in Plebe;us icarioides (Lycaeni­ dae ) 1. Food-plant specificity. J. Lepid. Soc. 15( 1) : 34-52. EHRLICH, P. R. & P. H. RAVEN. 1964. Butterflies and plants: a study in coevolu­ tion. Evolution 18: 586-608. GILBERT, L. E. 1971. The effect of resource distribution on population structure in the butterfly Euphydryas editha: Jasper Ridge vs. Del Puerto Canyon colonies. Ph.D. dissertation, Stanford University. SINGER, M. C. 1971. Evolution of food-plant preference in the butterfly Euphydryas editha. Evolution 25: 383-389. FOODPLANT ECOLOGY OF THE BUTTERFLY CHLOSYNE LACINIA (GEYER) (NYMPHALIDAE). 1. LARVAL FOODPLANTS RAYMOND \;y. NECK D epartment of Zoology, University of Texas at Austin, Austin, Texas 78712 For several years I have studied field populations of Chlosyne lacinia ( Geyer) (N ymphalidae: Melitaeini) in central and south Texas for genetic (Neck et aI., 1971) and ecological genetic data. A considerable amount of information concerning foodplants of this species has been collected. Foodplant utilization information is an important base from which ecological studies may emerge. Such information is also invaluable in evaluating the significance of tested foodplant preferences of larvae and adults. Such studies have been under way by other investigators and will be available for comparison with natural population observa­ tions. In addition to personal observations (which cover a four-year period encompassing some 20 generations), an extensive search of the literature reveals numerous, though scattered, previous reports of foodplants. Litera­ ture references to populations in central and south Texas are integrated into Table 1 with personal observations. All reports of foodplants outside the study area are discussed separately at the end of the study area foodplant discussion. Foodplants (see Table 1) are arranged into three basic categories ac- VOLUME 27, NUMBER 1 23 cording to their frequency of utilization by C. lacinia: I) major food­ plants, II) occasional foodplants, and III) rarely utilized foodplants. Obviously these three groups are arranged in a descending order of im­ portance. Within each group, however, foodplants are not arranged in any particular order of importance. The first three plants on the list are by far the most important foodplants of C. lacinia in central and south Texas. These three plants are the most prone of all foodplants (except #7 and # 10) to form large, nearly mono­ specific stands. Larval populations of C. harrisii have greater develop­ mental success in dense fields of the foodplant, Aster umbellatus, as a result of smaller inter-plant distances which allow more successful larval movement to fresh plants (Dethier, 1959), rather than as a result of greater foodplant biomass which would increase the number of oviposi­ tion sites. The last group of foodplants is almost negligible in importance and some records should be considered anomalous. These foodplants are included because some "anomalous" foodplants may be utilized at a high level under certain conditions (see foodplant #4). This latter group of plants might not fit the definition of a suitable foodplant given by Remington & Pease (1955) which is as follows: "A full test of the suitability of a plant requires that the larva be reared solely on that plant and that the adults be induced to mate and lay eggs which then hatch." In actuality, however, one plant species need not be the sole foodplant utilized in order to be considered a "full" foodplant (see Discussion). All food plant records are the result of adult female discrimination which resulted in oviposition of an egg mass (marked by "0" in Table 1) unless a particular record is cited as being larvae that have switched from another foodplant. Skeletonized leaf damage is typical of the gregarious early-ins tar larvae. Post-dispersal larvae of the fourth and fifth (final) ins tars chew holes through all leaf layers. Thus, it is quite simple to determine whether leaf damage typical of immature larvae is present. If none is present, the larvae are assumed to have switched from some other plant. In several instances larvae were actually observed while they were switching. This phenomenon of larval foodplant switch­ ing will be discussed in more detail elsewhere (Neck, in prep.). All observations within the study area involve the taxon of C. lacinia known as aclfutrix Scudder. Some references to populations in the western United States may refer to either acl;utrix or crocale (Edwards) or mixed populations of these two phenotypes. Records from Latin America refer to saunclersi (Doubleday), a term used to describe a form close to or in­ cluding aclfutrix (Higgins, 1960). toO TABLE 1. Larval foodplants of Chlosyne lacinia within the study area. II>. Plant species Code1 Tribe' Range (Texas) Habitat Previous Records I. Major foodplants 1. H elianthus annuus L. A-O Heliantheae (V) entire state, less com­ cleared ground and Kendall, 1959; Drum­ Common sunflower mon in east area dirt piles; various soils mond et al., 1970 but prefers clays 2·. Ximenesia encelioides Cav. A-O Heliantheae (V) most of state; rare in disturbed sandy soils Tinkham, 1944; Drum­ Cowpen daisy east area of fields and stream mond et a!., 1970 banks 3. Ambrosia trifida L. A -0 Heliantheae (A) entire state seasonally wet creek Kendall, 1959 Giant ragweed beds or floodph:ins II. Occasional food plants 4. Verbesina virginica L. P-O Heliantheae (V) eastern and central shaded woodlands and Kendall, 1959 -­o Frostweed areas thickets i ~ 5. Viguiera dentata (Cav.) P-O Heliantheae (V) central and western limestone outcroppings Drummond et a!., 1970 t"' Spreng. areas, especially Ed­ in cracks almost bare Sunflower goldeneye wards Plateau of soil ~ >-l 6. Zexmenia hispida (H.B.K.) P-O Heliantheae (V) Edwards Plateau, Rio limestone derived soils None ::t: Gray. Shrub daisy Grande Plains t'l t-< 7. H elianthus cucumerifolius A-O Heliantheae (V) eastern and central sandy soils Kendall, 1959 t'l '"tI T. & G. Cucumberleaf areas sunflower § '"tI t;j III. Rarely utilized food plants ;:: 8. Ambrosia artemisiifolia L. A- Heliantheae (A) all areas but Pan­ waste soil in full sun None '">-l Common ragweed handle and Trans­ or partial shade "'. Pecos en o 9. Parthenium hysterophorus L. A-O Heliantheae (A) all areas but east disturbed sites; vari- H. G. Lacey in Ken­ n S1 False ragweed ous soils dall & Kendall, 1971 ::l <:: o t"' q ;;<' ~ v-l TABLE 1. (Continued) zc: Trib:=" Range (Texas) Habitat s:: Plant species Code' Previous Records IJj t'1 10. R elianthus argophyllous A- Heliantheae (V) east central and coastal deep, loose sandy soils None !:Ij T. & C. Silverleaf plains ...... sunflower 11. Xanthium strumarium L. A-O Heliantheae (A) entire state moist disturbed sites None Cockleburr 12. Simsia calva (E. & G.) P- Heliantheae (V) south, central and dry soils Drummond et aI., 1970 Gray. Bushsunflower western areas 13. Calyptocarpus vialis Less. p-o Heliantheae south and central areas heavy soils None Prostrate lawnflower 14. Silphium sp. P-O Heliantheae central sector limestone knolls and R. o. Kendall in Rosinweed prairies Drummond et aI., 1970 15. Gaillardia pulchella A-? Heleniae all areas but east abandoned pastures, R. o. Kendall, pers. Foug. Firewheel fallow fields of vari- comm. ous soils 16. R eterotheca latifolia A- Astereae all areas sandy soils None Buck. Gamphorweed 1 A == annual, P == perennial; 0 == oviposition recorded under field conditions. • (V) == subtribe Verbesiinae; (A) subtribe Ambrosiinae. ~ ~ 26 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY Larval Foodplants Within Study Area The botanical nomenclature of Gould (1969) was followed. All lo­ calities, unless otherwise noted, are in central and south Texas. Obviously some plants not on this list may serve as foodplants, but, due to the time spent observing C. lacinia, all major and occasional foodplants utilized in this area are believed to be known. Various sources (Heiser, 1947; Shinners, 1958; Lynch, 1968; Gould, 1969; Correll & Johnston, 1970) were utilized to obtain the information on geographical range (within Texas) and preferred habitats of the various foodplants. This information is summarized in Table l. Helianthus annuus L. serves as the major foodplant from spring (first adults are normally seen around April 1 in Austin) until August. By August the great majority of these plants have become senescent due to hot, dry summer weather. The few sunflower plants that survive through summer until September rains occur are often able to survive until early winter. Larval broods have been found on this species as late as November (1971) in central Texas in favorable sites and years. Infestations have been found on H. annuus in deep south Texas (Santa Ana Wildlife Refuge) as late as the last week of December (1970). Although egg masses have been found on cultivated mono cephalic varieties of H. annuus, larval development does not appear to be as successful as on the wild form. Populations would not likely occur in cultivated fields of this species because of insecticidal treatments used against the sunflower moth, Homeosoma electellum (Phycitidae) (Teetes & Randolph, 1968). Ximenesia encelioides Cav. is by far the major foodplant of C. lacinia from August (Drummond et a!., 1970) until the end of the larval feeding period in November or early December. Although this annual germinates in the spring (February), most seedlings grow rather slowly until late summer rains occur (normally in September). These plants then grow rapidly and are able to support huge larval populations. Ambrosia trifida L. serves as a foodplant only when there is a nearby population of C.