Seasonal fluctuations and phenology of Prosapia spittlebugs (Homoptera : Cercopidae) in upland pastures of Costa Rica

Seasonal fluctuations in Prosapia (Homoptera: Cercopidae) abundance were do cumented over 4 yr in 3 upland dairy pastures of Costs Rica. P. nr bicincta (Say) completed only 1 relatively long-lived generation each year between May and September. First instars appeared in May at the start of the wet se ason, progressed through 5 instars and peaked in abundance in mid-June. Den sities as high as 277 spittlebugs per square meter were reached. Adult popu lations peaked late June to early July and achieved densities up to 260 fro ghoppers per 50 sweeps of an insect net. Distinct peaks of adult males gene rally occurred 3-4 wk in advance of the maturation of 5th instars and the p rincipal adult peaks. Males outnumbered females 5.6:1 in sweep net surveys. Nymph and adult abundance fluctuated widely among paddock-years in no clea r pattern with respect to paddock or predominant forage. Phenological analy ses based on cumulative insect-days did not detect differences in populatio n initiation or development rate across paddock-years. Teneral and. adult m ales peaked earlier than their respective females (protandry). In 5 of 8 an d 4 of 9 paddock-years, adult males and females, respectively, peaked in ab undance before same sex tenerals, indicating colonization of local pastures . Additional evidence for immigration was the abrupt appearance of male P. simulans (Walker) at the same time in all paddocks each year. This species did not complete its life cycle in local pastures because females and nymph s were absent from surveys. Explorations of pastures at varying elevation a nd distance from survey paddocks demonstrated that within 10 km P. nr bicin cta populations matured 2.5 wk earlier. Adults derived from these populatio ns may become available as colonists to local pastures. The nearest breedin g populations of P, simulans to sites where males were recovered were 485 m lower in elevation and 3.4 km distant.