Figure 2.

Variation in nuptial gift size (spermatophores) is observed to correspond to male accessory gland size, and this variation extends to the male contribution to egg production in Parachauliodes continentalis and Protohermes grandis. (a) A small spermatophore produced by male Pa. continentalis (left) and a large spermatophore with yellowish gelatinous substrate produced by male Pr. grandis (right). (b) Light (top) and fluorescence (bottom) photographs of male internal reproductive organs excluding the testes of rhodamine-free and rhodamine-fed Pa. continentalis (left two) and Pr. grandis (right two). Red fluorescence in rhodamine-fed males of each species. (c,d) Ovarioles of female Pa. continentalis mated once with rhodamine-free (control) males (c) and those mated once or three times with rhodamine-fed males (d). In both cases, no fluorescent signals were detected. (e–g) Ovarioles of female Pr. grandis mated once with rhodamine-free (control) males (e) and those mated once or three times with rhodamine-fed males (f,g). In (f), fluorescent signals were detected at the end of a row of mature eggs (indicated by arrowheads). In (g), the fluorescent signals were also detected in each egg of the row of mature eggs.