Phoretic copulation in the velvet ant Sphaeropthalma pensylvanica (Lepeletier) (Hymenoptera, Mutillidae): A novel behavior for Sphaeropthalminae with a synthesis of mating strategies in Mutillidae

Abstract

Phoretic copulation, a form of phoresy in which a male physically transports a female by flight and/or foot from their initial site of contact before mating, is newly recorded in the Nearctic velvet ant Sphaeropthalma pensylvanica (Lepeletier, 1845) (Hymenoptera: Mutillidae). Further, this is the first record of the behavior in the species-rich subfamily Sphaeropthalminae. A description of the S. pensylvanica mating observation and photographs are provided. All published observations of copulation events in Mutillidae are critically reviewed in the context of mating strategy, and new terminology is proposed for the mating strategies currently known to occur in the family.

Love is in the air and beyond the ocean: Taxonomic review ofNeotrogaspidiaLelej (Hymenoptera: Mutillidae: Trogaspidiini) in Northeast Asia highlights its unique distributional pattern

“…Neotrogaspidia species meet the size prerequisite for phoretic copulation with males being larger than females (Evans 1969;Deyrup & Manley 1986;Waldren et al 2020). The body length of N. pustulata examined here, 7.53-16.7 (11.5 AE 1.39) mm for males and 4.17-9.94 (7.28 AE 1.21) mm for females (n = 122♂130♀), suggests utilization of multiple host species with variable body size and size-dependent sex allocation (Pitts et al 2010a).…”

“…The mating biology, habitats and hosts have been largely unknown for Neotrogaspidia, even though N. pustulata is one of the most commonly encountered mutillids in Japan. Observations by Japanese entomologists revealed that this species practices mandibular phoretic copulation (Waldren et al 2020). The Neotrogaspidia males have the morphological traits associated with prolonged phoretic copulation, like the concaved clypeus and the baso-ventral mandibular tooth (Crèvecoeur 1930;Sheldon 1970).…”

“…In particular groups of mutillids, males are as large as or even smaller than females and are physically unable to carry females (Waldren et al . 2020). Alternative mating strategies may provide varied dispersal ability to females, resulting in incongruent distributional patterns across taxa.…”

“…This behavior is considered a method to overcome geographic barriers for females (Evans 1969), although the adaptive merit of phoretic copulation has not been fully elucidated. An alternative mating strategy is in situ copulation, in which mating events take place at or near the site of initial contact between a male and a female (Waldren et al 2020). In particular groups of mutillids, males are as large as or even smaller than females and are physically unable to carry females (Waldren et al 2020).…”

“…An alternative mating strategy is in situ copulation, in which mating events take place at or near the site of initial contact between a male and a female (Waldren et al 2020). In particular groups of mutillids, males are as large as or even smaller than females and are physically unable to carry females (Waldren et al 2020). Alternative mating strategies may provide varied dispersal ability to females, resulting in incongruent distributional patterns across taxa.…”