Contrasts in Reproductive Ecology Between Temperate and Tropical Populations of Jadera haematoloma, a Mate-Guarding Hemipteran (Rhopalidae)

Abstract

Field studies of the effect of climate and host-plant phenology on reproductive patterns of the seed-feeding Jadera haematoloma Herrich-Schaeffer were undertaken in Oklahoma and Florida. In Oklahoma, most reproduction is confined to August and September, when seeds of the sapindaceous host trees, Sapindus saponaria L. var. drummondii (Hooker & Arnett) (Benson) and Koelreuteria paniculata (Laxman), are mature, and is followed by a reproductive diapause in winter. The proportion of females becoming reproductive in their natal year declined from August to September. Diapause occurred while food was still available and is probably photoperiodically induced. In Florida, most reproduction occurred in April–May and November–January, when seeds of the sapindaceous vine, Cardiospermum corindum L., were available. Diapause here occurred when seeds were unavailable. Bugs in Florida are larger, take longer to mature, and produce larger eggs, at a slower rate, that take longer to hatch, than those in Oklahoma. Greater mortality of females as overwintering adults and as nymphs in summer contributed to a strong male-bias in the adult sex ratio of Oklahoma aggregations, whereas sex ratios in Florida were not male-biased. It was therefore predicted that Oklahoma males might guard their mates from other males, whereas those in Florida would not. However, males in both populations were found to prevent females from mating with other males by remaining in copula from the time of intromission until oviposition. Contact guarding continues during oviposition and the pair may recouple afterwards. Postinsemination guarding, although not predicted by Florida sex ratios, may occur there because of greater last-male sperm precedence in that population than in Oklahoma.