@article {22982, title = {Wettability and morphology of proboscises interweave with hawkmoth evolutionary history}, journal = {Journal of Experimental Biology}, volume = {226}, year = {2023}, month = {10/2023}, pages = {jeb245699}, chapter = {jeb245699}, abstract = {

Hovering hawkmoths expend significant energy while feeding, which should select for greater feeding efficiency. Although increased feeding efficiency has been implicitly assumed, it has never been assessed. We hypothesized that hawkmoths have proboscises specialized for gathering nectar passively. Using contact angle and capillary pressure to evaluate capillary action of the proboscis, we conducted a comparative analysis of wetting and absorption properties for 13 species of hawkmoths. We showed that all 13 species have a hydrophilic proboscis. In contradistinction, the proboscises of all other tested lepidopteran species have a wetting dichotomy with only the distal ~10\% hydrophilic. Longer proboscises are more wettable, suggesting that species of hawkmoths with long proboscises are more efficient at acquiring nectar by the proboscis surface than are species with shorter proboscises. All hawkmoth species also show strong capillary pressures which, together with the feeding behaviors we observed, ensure that nectar will be delivered to the food canal efficiently. The patterns we found suggest that different subfamilies of hawkmoths use different feeding strategies. Our comparative approach reveals that hawkmoths are unique among Lepidoptera and highlights the importance of considering the physical characteristics of the proboscis to understand the evolution and diversification of hawkmoths.

}, keywords = {ADULT FEEDING, AGRIUS, CAPILLARY PRESSURE, CONTACT ANGLE, DARAPSA, DOLBA, ENYO, EUMORPHA, FEEDING EFFICIENCY, FLUID DYNAMICS, FLUID-STRUCTURE INTERACTION, HEMARIS, HYLES, MANDUCA, MENISCUS, PARATREA, PROBOSCIS, SPHINGIDAE, XYLOPHANES}, doi = {10.1242/jeb.245699}, author = {Palaoro, A.V. and Gole, A.R. and Sun. Y. and Puchalski, A. and Beard, C.E. and Adler, P.H. and Kornev, K.G.} } @article {22076, title = {Diel rhythms and sex differences in the locomotor activity of hawkmoths}, journal = {Journal of Experimental Biology}, volume = {220}, year = {2017}, pages = {1472-1480}, chapter = {1472}, abstract = {

\"Circadian patterns of activity are considered ubiquitous and adaptive, and are often invoked as a mechanism for temporal niche partitioning. Yet, comparisons of rhythmic behavior in related animal species are uncommon. This is particularly true of Lepidoptera (butterflies and moths), in which studies of whole-animal patterns of behavior are far outweighed by examinations of tissue-specific molecular clocks. Here, we used a comparative approach to examine the circadian patterns of flight behavior in Manduca sexta and Hyles lineata [two distantly related species of hawkmoth (Sphingidae)]. By filming isolated, individual animals, we were able to examine rhythmic locomotor (flight) activity at the species level, as well as at the level of the individual sexes, and in the absence of interference from social interaction. Our results confirmed classic descriptions of strictly nocturnal behavior in M. sexta and demonstrated a dramatically different activity pattern in H. lineata. Furthermore, we showed distinct species and sex-specific differences in the maintenance of the endogenous rhythm under conditions of constant darkness. In both species, female activity peaked in advance of males whereas male activity coincided with periods of female sexual receptivity. This suggests a role for circadian patterns of locomotor activity in synchronizing periods of sexual receptivity between the sexes.\"

}, keywords = {CALLING TIME, CIRCADIAN RHYTHMS, DIEL ACTIVITY, FLIGHT PERIOD, HYLES, MANDUCA, SEXUAL DIMORPHISM, SPHINGIDAE}, doi = {10.1242/jeb.143966}, author = {Broadhead, G.T. and Basu, T. and von Arx, M. and Raguso, R.A.} }