Species and Sex Differences in Eye Morphology and Visual Sensitivity of Two Nocturnal Sweat Bee Species (Megalopta Spp., Hymenoptera: Halictidae)

34 Pages Posted: 23 Oct 2019

See all articles by Beryl Jones

Beryl Jones

Princeton University

Brett Seymoure

Washington University; St. Louis University; Colorado State University

Troy Comi

Princeton University

Ellis Loew

Cornell University

Date Written: October 14, 2019

Abstract

Visually dependent dim-light foraging has evolved repeatedly across taxa, broadening species ecological niches. As most dim-light foraging species evolved from diurnal ancestors, visual sensitivity must increase immensely to compensate for light levels a billion times dimmer than daylight. Some taxa, e.g. bees, are anatomically constrained by their apposition compound eyes, which function well in daylight but not starlight. However, the sweat bee genus Megalopta has incredibly sensitive eyes, foraging in light levels up to 9 orders of magnitude dimmer than diurnal relatives. Despite years of behavioral study, variation in visual sensitivity and eye morphology has not been investigated within and across different Megalopta species. We describe eye morphology for two sympatric species of Megalopta, M. genalis and M. amoena, which both forage during twilight under little light. We use electroretinograms to find that males, which are smaller than females, have increased retinal sensitivity compared to females. Although males have relatively larger eyes compared with females, morphological features of the eye were not correlated with retinal sensitivity, suggesting males have additional adaptations to improve retinal sensitivity. These findings are foundational for future work into neural and physiological mechanisms that interface with morphology to increase visual sensitivity.

Keywords: allometry, compound eye, electroretinograms, eye morphology, facets, nocturnal foraging, visual sensitivity

Suggested Citation

Jones, Beryl and Seymoure, Brett and Comi, Troy and Loew, Ellis, Species and Sex Differences in Eye Morphology and Visual Sensitivity of Two Nocturnal Sweat Bee Species (Megalopta Spp., Hymenoptera: Halictidae) (October 14, 2019). Available at SSRN: https://ssrn.com/abstract=3469351 or http://dx.doi.org/10.2139/ssrn.3469351

Beryl Jones

Princeton University ( email )

22 Chambers Street
Princeton, NJ 08544-0708
United States

Brett Seymoure (Contact Author)

Washington University ( email )

One Brookings Drive
Campus Box 1208
Saint Louis, MO MO 63130-4899
United States
2695018761 (Phone)

St. Louis University ( email )

3511 LaClede Avenue
St. Louis, MO 63103
United States

Colorado State University ( email )

Fort Collins, CO 80523-1771
United States
269 501 8761 (Phone)

Troy Comi

Princeton University ( email )

22 Chambers Street
Princeton, NJ 08544-0708
United States

Ellis Loew

Cornell University ( email )

Ithaca, NY 14853
United States

Here is the Coronavirus
related research on SSRN

Paper statistics

Downloads
10
Abstract Views
95
PlumX Metrics