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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Pest Management Research » Research » Publications at this Location » Publication #400482

Research Project: Biological Control and Habitat Restoration for Invasive Weed Management

Location: Pest Management Research

Title: Sexual dimorphism in excess power index of four North American native bees (Hymenoptera, Andrenidae, Apidae, and Halictidae)

item VIGUEIRA, PATRICK - High Point University
item VIGUEIRA, CINDY - St Louis University
item Campbell, Joshua
item LADNER, SAMIA - High Point University
item HAYES, GABRIELLE - High Point University
item RISER, ELIZABETH - High Point University

Submitted to: Journal of Hymenoptera Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2023
Publication Date: 4/11/2023
Citation: Vigueira, P.A., Vigueira, C.C., Campbell, J.W., Ladner, S., Hayes, G., Riser, E. 2023. Sexual dimorphism in excess power index of four North American native bees (Hymenoptera, Andrenidae, Apidae, and Halictidae). Journal of Hymenoptera Research. 96:121-128.

Interpretive Summary: Many native bee species exhibit morphological differences between sexes. These differences can reflect different behaviors and roles the different sexes perform. The excess power index (EPI) is a mathematical formula based on several morphological measurements that is used to estimate flight performance in insects. We compared female and male EPIs in four native bee species. In all four species, males had a larger EPI whereas females had a larger body mass. The ecologies of most native bee species are relatively unknown. Thus, the use of EPI in native bees can be used to infer behavioral differences between sexes.

Technical Abstract: A multitude of hymenopteran species exhibit sexual dimorphism for simple traits, such as color, size, or antennal segment number. These differences can reflect selection for specialized biological roles, many of which have not been documented for the majority of bee and wasp species. The excess power index (EPI) is an estimate of insect flight performance that is inferred by the combination of several morphological characteristics. We compared the female and male EPIs in four species of native bees: Agapostemon virescens, Andrena carlini, Melissodes bimaculata and Xylocopa virginica. While females of each species had a significantly larger whole body mass, males had a significantly larger EPI. A larger body mass for females is associated with egg laying abilities and foraging behavior. Male fitness may be dependent on EPI; males that have greater flight capacity can travel further or remain in flight for longer time periods in search of mates.