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Volume 33, Number 1
57
Novitates Zool. 13: 27-753; Tyler, op. cit.); larval foodplants are various species of Aristolochia (e.g., Tyler, op. cit.). This note reports an observation of oviposition of B. belus varus on a plant other than a larval foodplant.
On 19 February 1977, a female B. belus varus was observed flying among several clumps of woody and herbaceous vines in a secondary forest at Finca La Tigra, near La Virgen de Sarapiqui, Heredia Province, Costa Rica. She finally began ovipositing on a vine, Melothria guadelupensis (Spreng.) Cogn. (Cucurbitaceae), intertwined with another vine, Aristolochia constricta Griseb.; the leaves of the two plants were similar in size and general shape. Oviposition lasted several minutes (Fig. 1). Forty-three eggs were deposited in a tight cluster on a single leaf of M. guadelupensis and no eggs were found on the A. constricta. In the laboratory, the freshly hatched larvae did not accept leaves of M. guadelupensis, but fed briefly on A. ringens Vahl (obtained from H. W. Pfeifer in 1971; locality not specified) before dying. Aristolochia constricta was not available for testing.
Tyler (op. cit.) mentions that B. philenor accepts only certain species of Aristolo-chiaceae as foodplants. Foodplant specificity is apparent where different species of Aristolochia occur in the same region (Scriber & Feeny 1976, J. Lep. Soc. 30: 70-71). An Australian Aristolochia-ieeding swallowtail, Ornithoptera priamus, has been observed to deposit eggs on an introduced species of Aristolochia, and the larvae perished (Straatman 1962, J. Lep. Soc. 16: 99-103). The refusal of A. ringens, a plant species native to Costa Rica, by B. belus larvae, supports the possibility that Battus specializes on restricted larval foodplants within the Aristolochiaceae. Eggs of B. nhilenor have been found on Convolvulaceae and Polygonaceae, vines which generally look like Aristolochia. Larvae of another Aristolochia-ieeding swallowtail, Polydorus aristolochiae (Fabricius), have been seen on various Cucurbitaceae in India, but their larvae refused to accept these plants in captivity (Ghosh 1914, Mem. Dept. Agr. India, Entomol. Sec. V(l): 53-587). Only certain species of Aristolochia are food-plants of P. aristolochiae (Munshi & Moiz 1967, J. Lep. Soc. 21: 127-128). It is possible that B. belus varus mistook the cucurbit vine for an Aristolochia. Perhaps the very close proximity of the A. constricta vine contributed to this confusion, by providing odoriferous and visual properties of a correct foodplant. Alternatively, the oviposition on the intertwined cucurbit might have been deliberate, possibly representing an adaptation to avoid waiting egg parasites and predators. Under this explanation, the newly hatched larvae would have rapidly found the correct foodplant. Further observations are needed to distinguish between these two hypotheses. If an adaptation for avoiding egg parasites and predators, such behavior might be more prevalent among vine-feeding butterflies in the tropics, where the intertwining of unrelated vines is common.
Allen M. Young, Invertebrate Division, Milwaukee Public Museum, Milwaukee, Wisconsin 53233.
Journal of the Lepidopterists' Society 33(1), 1979, 57-58
MALFUNCTION OF ECDYSIS ALLOWING IMAGINAL EMERGENCE
BUT CAUSING DEATH OF ADULT HACKBERRY BUTTERFLY
(NYMPHALIDAE)
Insects must periodically shed their skins—a process known as ecdysis which allows growth or transformation of the individual. Each molt period is a dangerous time during which the insect is susceptible to predation or physiological malfunctioning, both of which may cause death. Natural selection has, therefore, perfected the process of ecdysis to such a degree that physiological failures are rare. I describe
58
Journal of the Lepidopterists' Society
below the partial failure of an act of ecdysis—a developmental malfunction which did not prevent transformation, but one that was eventually fatal to the butterfly involved. Such malfunctions are not uncommon in laboratory cultures; however, this observation is of interest because it involved a wild-caught adult.
On 17 July 1977 at 1100 hours CDT, I was handed an adult female Asterocampa celtis antonia (Edwards) which had been hand-collected in a residential backyard in Austin, Travis County, Texas. Lack of worn spots on the fully expanded wings, occasional release of untransformed fluids and an egg-packed abdomen indicated recent emergence, probably that same morning. I soon discovered that the head was covered with partial exuviae which had not been properly shed. Practically the entire chrysalid head capsule was still present covering the greater part of the imaginal head. Additionally, the left side of the larval head capsule was still attached to the outside of the chrysalid head capsule.
Upon metamorphosis of the prepupa to pupa, the left half of the final-instar larval head capsule failed to separate from the newly formed pupal epidermis. When imaginal emergence occurred, both sides of the pupal "head" failed to separate as a result of mechanical restriction caused by the still-present larval head capsule section.
Although the adult was able to emerge and properly expand and dry its wings, damage to selected parts of the head effectively negated any chance that this individual would reproduce. Both eyes appeared completely normal and allowed reaction to approaching objects. The left antenna was not visible, having been transformed into an unrecognizable mass associated with the remnant exuviae. The right antenna was free and fully developed; however, it was flexed laterally and horizontally (about 75° from perpendicular) about 2 mm from its base. This antenna could be moved at its base, but such movements occurred only when the antenna was touched; no spontaneous movements were observed. The most significant damage affecting the fitness of this individual involved its proboscis. The proboscis was entirely nonfunctional because of failure of the two maxillae to properly fuse. The two halves adhered to each other in a haphazard manner and to the remaining exuviae; removal of the exuviae was accompanied by removal of the proboscis halves.
Lack of a functional proboscis caused early death of this individual, because the butterfly was unable to feed or obtain moisture. This damaged individual grew progressively weaker until it died approximately 75 hours following capture (in a cage at an ambient diurnal temperature range of about 25-35°C). I thank Patrick K. Neck for supplying the specimen.
Raymond W. Neck, Pesquezo Museum of Natural History, 6803 Esther, Austin, Texas 78752.
Journal of the Lepidopterists' Society 33(1), 1979, 58-60
AGGREGATIVE BEHAVIOR OF ANARTIA FATIMA (NYMPHALIDAE) IN GUANACASTE PROVINCE, COSTA RICA DURING THE DRY SEASON
The neotropical butterfly Anartia fatima Fabricius (Nymphalidae: Nymphalinae) is widespread throughout the coastal wet and dry regions of Central America and northern South America (Godman & Salvin 1879, Biologia Centraliamericana, Insecta, Lepidoptera-Rhopalocera, vol. 1, 487 p.). Several larval foodplants, in the Acanthaceae, are shared with other nymphalines such as Siproeta (Young & Muyshondt 1974, Stud. Neotrop. Fauna 9: 155-176), but during the severe dry season of dry regions these plants exhibit leaf drop and become unsuitable for oviposition (Young & Stein 1975, Contr. Biol. & Geol., Milwaukee Pub. Museum, No. 8, 29 p.). Several years of observing A. fatima populations in the lowland tropical dry forest region (Tosi 1969, Mapa