On polyphenism of Eurema daira in Florida
 


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Sourakov, A. 2009. On polyphenism of Eurema daira in Florida.  News of Lepidopterists’ Society. 51(1): 38-40.

 

Here, I present a short photo essay, depicting two seasonal forms of Barred Yellow butterfly, Eurema daira.  Daniels (1995) suggested that the observed seasonal polyphenism “may enhance thermoregulation and/or crypsis for dry season form individuals faced with cooler conditions and distinctly different vegetative landscapes.” The photographs presented here that were taken in July (A, B) and December (C, D) at the same hour and on the same spot support crypsis theory.  The observed changes in coloration seem to also correspond to changes in behavior.  While in the summer, a disturbed E. daira tends to escape into the vegetation and hide under leaves, where it can be easily mistaken for one of the numerous white flowers, the winter form seeks refuge on the ground, blending with the fallen leaves. 

 Brakefield and Larsen (1984) argue, that dry season and wet season divergent phenotypes of Bicyclus are nothing else but anti-predator adaptations. The wet season form’s large eyespots, they suggest, function in the deflection of attacks, while the dry season individuals that have small or no spots are cryptic. They note that change in this species also corresponds to behavior: wet season butterflies are more active than dry season ones and, as they put it, “reproductive success is optimized in each season by interaction of phenotype and behavior.”  

 It has been suggested that “the phenotypic plasticity is to be expected to be built in every genome for every character since it is the primitive character that is governed by physiological processes sensitive to such environmental variables as temperature, nutrient supply, ionic environment...”  Frederick Nijhout’s laboratory at Duke University has been making a tremendous progress in understanding physiology of phenotypic plasticity in Lepidoptera (e.g., Rountree and Nijhout, 1995; Suzuki and Nijhout, 2008).  These studies suggest that a mutation that makes the phenotype sensitive to environmental and genetic changes at a single locus can uncover cryptic genetic variation for plasticity.  Nijhout’s model assumes presence of selective pressure (such as predators) on continuous polygenic reaction norm, which leads to evolution of distinct phenotypes, suggesting therefore that evolution of polyphenism is “consistent with the adaptive evolution theory.”  Though selectionist explanations have led evolutionary ecologists astray in the past (as it might have been the case with industrial melanism in peppered moths (Hooper, 2002)), such explanations are as highly probable, as their ecological testing is difficult. 

Seasonal forms of Eurema daira (Pieridae) in Florida exhibiting season-specific crypsis. ©Andrei Sourakov


References

Brakefield P. M. & T. B. Larsen 1984. The evolutionary significance of dry and wet season forms in some tropical butterflies. Biol J Linn Soc 22: 1-12.

Daniels J. C. 1995. Seasonal variation in the little sulphur butterfly, Eurema lisa lisa, in central Florida: how it compares to other sympatric EuremaHolarctic Lepidoptera 2(2): 59-65). species (Lepidoptera: Pieridae).

Hooper J. 2002. Of the Moths and Men: An Evolutionary Tale. W.W. Norton & Co., 377 p.

Rountree, D. B. & H. F. Nijhout. 1995. Genetic Control of a Seasonal Morph in Precis coenia (Lepidoptera: Nymphalidae). J. Insect Physiol. Vol. 41, No. 12, pp. 1141-1145.

Suzuki, Y. & H. F. Nijhout. 2008. Genetic basis of adaptive evolution of a polyphenism by genetic accommodation. J . Evol. Biol., 21 57–66.

 


 

Direct competition for nectar in some Patagonian butterflies

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Sourakov, A. 2009. Direct competition for nectar in some Patagonian butterflies.  News of Lepidopterists’ Society. 51(1): 14-15.  


Ritual fighting is common among butterflies, but the physical violence is rarely observed.  However, it does occur.  Intraspecific violence has been observed between males of Papilio indra, which are territorial to the extent that they can tear each other to pieces (Eff, 1962).  Physical competition among males for a place on a female pupa is found in Heliconius (e. g., Sourakov, 2008). Males of monarchs and some other butterflies attempt forceful mating with females (e.g., Frey, 1997). 

Here I present an example of apparent physical competition that does not involve sexual selection, but involves interspecific competition for food among three species of Nymphalidae from Patagonia.  In February 2008, I observed how Vanessa terpsichore was repeatedly attacked by Cosmosatyrus leptoneuroides in the southern Andes, Patagonia, Argentina.  Male of the latter butterfly species came repeatedly towards male of V. terpsichorefeeding on a nectar source, which was attractive to many butterflies in the area. Each time, it came into brief physical contact with the feeding butterfly. Similar behavior was exhibited by another nymphalid, Yramea cytheris. I did not observe such behavior on an intraspecific level, though there were many opportunities. Neither attacker was successful in dislodging V. terpsichore from the flowers, although they created sufficient discomfort for it to start flapping its wings.  The photos presented here were created by capturing individual frames from a digital video. Thanks to George Austin for bringing one of the references to my attention.


References

Eff, D. 1992. A little about the little-known Papilio indra minori. J. Lep. Soc. 16(2): 137-142.

Frey D. 1997. Resistance to mating by female monarch butterflies. North American Conference on the Monach Butterfly, Jürgen Hoth (editor). 428 pages.

Sourakov A., 2008. Pupal mating in Zebra longwing (Heliconius charithonia): photographic evidence. News of Lepidopterists’ Society. 50(1): 26-29, 32.

 

 

 

 Fierce Faces of Florida Tigers: Moths Mimicking Spiders

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Sourakov, A. 2013. Fierce faces of Florida tigers: moths mimicking spiders. News of Lepidopterists’ Society 55(2): 60-61.

 

Tigers stock their prey, then jump to bring it down. So do the jumping spiders, but nobody calls them “tiger spiders.” Instead, the “tiger” epithet is reserved for the docile tiger moths, which to my knowledge never pounced on or bit anybody, and whose evasive action is usually limited to playing dead and falling in an awkward position into the grass, from which there is long and painful way up through the vegetation populated by spiders. Nevertheless, tiger moths are not defenseless: they carry noxious chemicals that protect them from the predators.

Perhaps not coincidentally, the moths may have some markings on their front ends that resemble those of the spiders. When they crawl up a stem or reach a flower, the most probable way for them to meet with a spider or another predator is going to be “face-to-face.” For instance, the giant leopard moth, Hypercombe scribonia, carries iridescent markings on its head and thorax resembling those of the regal jumping spider, Phidippus regius, which has iridescent chelicerae, and its legs are patterned like those of the spider (Fig. 1).  The ornate bella moth, Utetheisa ornatrix, has on its thorax a pattern that closely resembles that of the spinybacked orbweaver, Gasteracantha cancriformis. The resemblance is even more pronounced before the moth spreads its wings.

Howse and Allen (1994) refer to this type of mimicry as ‘Satyric Mimicry,’ or the previously introduced by Rothschild (1984) concept of 'Aidemémoire Mimicry' can be used to describe patterns that make predators recall a revolting encounter.

Recently, Rota and Wagner (2009) managed to experimentally prove that mimicking jumping spiders works for moths as a defense against the spiders themselves. They conducted well-designed controlled experiments, in which Brenthia metalmark moths (Choreutidae) were confronted with their supposed models – the solticid spiders, Phiale formosa, and the spiders mistook the moths for conspecific spiders - instead of attacking, they reacted with a display behavior. It is possible that the coloration of the moths featured in the present essay is also directed against the spiders they mimic. It is more likely, however, that the spiders and the tiger moths form Müllerian mimicry complexes: the toxic moths and the biting spiders are repugnant to a wider variety of predators including birds, mammals and invertebrates (e.g., Eisner and Eisner 1981). Experimental work proving the effectiveness of these patterns in instilling unpleasant memories in predators would be of great value to our understanding of mimicry.

 

 

the regal jumping spider, Phidippus regius.

 

 

giant leopard moth, Hypercombe scribonia,

 A case of aide mémoire or satyric mimicry: the giant leopard moth, Hypercombe scribonia, and the regal jumping spider, Phidippus regius.

(Photos are by Andrei Sourakov, all rights reserved)

 

 

Literature Cited:

Eisner, T. and M. Eisner. 1991. Unpalatability of the pyrrolizidine alkaloid containing moth, Utetheisa ornatrix, and its larva, to wolf spiders. Psyche. 98: 111-118

Howse, P. E. and J. A. Allen. "Satyric mimicry: the evolution of apparent imperfection." Proceedings of the Royal Society of London. Series B: Biological Sciences. 257.1349 (1994): 111-114.

Rota, J. and D. L. Wagner. 2006. Predator mimicry: metalmark moths mimic their jumping spider predators. PLoS One. 1:e45.

Rothschild, M. 1984 Aide mémoire mimicry. Ecological Entomology. 9: 311-319.


 

 

 

The Tropical Swallowtail Moth, Lyssa zampa (Uraniidae) – another victim of lymph-thirsty parasites in Vietnam

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Sourakov, A. 2013. The Tropical Swallowtail Moth, Lyssa zampa (Uraniidae) – another victim of lymph-thirsty parasites in Vietnam. News of Lepidopterists’ Society 55(3): 106-107.

The mosquitoes were out at night at Bach Ma National Park, and I was advised to wear repellent to avoid possible diseases (malaria and Japanese encephalitis), though both are highly unlikely in Vietnam.  On that evening, I was not the only one who was unwillingly sharing my blood with the biting dipterans at the collecting light. One of the most prevalent species that visited the sheets was the Tropical Swallowtail Moths, Lyssa zampa (Butler) (Fig. A). It was the largest moth that I had seen during the two weeks of black-lighting in north-central Vietnam in May, 2013, but only in Bach Ma, at an elevation of 1,200 meters, did I notice several biting midges feeding on one of them (Fig. B). The midges were amber in color, and about 1 mm in size.

I observed four midges on the same moth simultaneously (Fig. B), with their mouthparts clearly at work. It has been suggested previously (Kawahara et al. 2006 and references within), that the observed uniform orientation of these midges (their heads pointed towards the wing base) is not incidental, but is determined by their unique functional morphology. Apparently, the midges have a special spine and a comb on each of their tarsal claws, which allow them to cling to the Lepidoptera scales. While two of the midges biting Lyssa zampa were feeding on the hindwing, in close proximity to the veins surrounding the wing cell (Fig. B), another midge was feeding on the forewing close to hind margin (Fig. C), and the fourth on the abdomen (Fig. D).

Kawahara et al. (2006) reported the midges feeding on 10 different species of Geometridae in Malaysia and Taiwan, and identified them as Forcipomyia pectinunguis (de Meijere) (Diptera: Ceratopogonidae). Unlike the midges pictured here, all F. pectinunguis were observed feeding close to the forewing base near the veins. According to Bill Grogan at the Florida State Collection of Arthropods (pers. com.), who recently co-authored an article on biting midges attacking butterfly caterpillars in Florida (Koptur et al., 2013), the midges that I observed in Vietnam are most likely of another Forcipomyia species in the subgenus Trichohelea.  Thus, the present report likely expands the recorded host range of Forcipomyia to yet another Lepidoptera family. 

Lyssa macleayi (closely related to L. zampa) sequesters alkaloidal glycosidase inhibitors (AGIs) from its hostplant Endospermum medullosum (Euphorbiaceae) (Kite et al. 1991), and it is very likely that L. zampa does so as well as it too feeds on Endospermum(Yen et al. 1995). If it indeed possesses such biologically active anti-feeding compounds, the biting midges are clearly not repelled by them.

 

 

Figure 1. Lyssa zampa (Uraniidae) attacked by biting midges Forcipomyia sp. (Diptera: Ceratopogonidae), Bach Ma National Park, Vietnam.

(Photos by Andrei Sourakov, all rights reserved)

 

 

Literature Cited:

Kite, G. C., L. E. Fellows, D. C. Lees, D. Kitchen, and G. B. Monteith. 1991. Alkaloidal glycosidase inhibitors in nocturnal and diurnal Uraniine moths and their respective foodplant genera, Endospermum and Omphalea. Biochemical Systematics and Ecology. 19(6): 441-445.

Kawahara, A. Y., I. S. Winkler, and W. W. Hsu. 2006. New host records of the ectoparasitic biting midge Forcipomyia (Trichohelea) pectinunguis (Diptera: Ceratopogonidae) on adult geometrid moths (Lepidoptera: Geometridae). Journal of the Kansas Entomological Society. 79(3): 297-300.

Koptur S., J. E. Pena, and W. L. Gragan Jr. 2013 The biting midte Forcipomyia (Microhelea) eriophora (Williston) (Diptera: Ceratopogonidae), an ecotoparasite of larval Phoebis sennae (Pieridae) in South Florida. Journal of the Lepidopterists’ Society. 67(2): 128-130.

Yen, S. H., H. S. Yu, J. H. Mu, and H. J. Tan. 1995. On Lyssa zampa (Butler, 1867) (Uraniidae) from Taiwan.

Japan Heterocerists’ Journals. 186:173-175.