Demographic study of the reproductive potential of pear psylla,Cacopsylla pyri

Abstract

Longevity and fecundity of pear psylla adults, Cacopsylla pyri (L.) (Homoptera: Psyllidae), were studied in Greece under field conditions, during 1991/92 and 1992/93. Net fecundity (mean fecundity of cohort) of the overwintered females (winter form) was low (24.1 and 43.4 eggs per female for 1991/92 and 1992/93 respectively) because only a small fraction of the females survive reproductive diapause. Surviving females, however, are capable of producing a relatively high number of eggs (135.0 and 151 9 eggs per female for the two seasons respectively). Net fecundity of summer form females was very high in spring (343.2 and 406.8 eggs per female for 1992 and 1993 respectively), relatively high in early autumn (130.4 and 192.5 eggs per female) and very low in summer (21.9 and 46.5 eggs per female). Male longevity was in all cases shorter than that of female. Longevity of both sexes of the summer form was higher in spring and autumn (for females it ranged from 22.3 to 28.4 days) than it was in summer (for females it ranged from 14.3 to 17.4 days).

Biological control in winter: novel evidence for the importance of generalist predators

“…The model revealed that winter‐active predators dramatically suppressed the density of Cacopsylla during winter. Although the Cacopsylla population may suffer high mortality during winter caused by factors other than predation (Fye ; Kapatos & Stratopoulou ), they possess very high fecundity; thus, without suppression by winter‐active predators, the population would most likely outbreak quickly. Winter‐active spiders can thus be considered as very effective generalist biocontrol agents.…”

Is there reproductive diapause in the winterform of pear psylla Cacopsyla bidens?

“…Similar to other insect species, many psyllids of temperate regions overwinter as adults in reproductive diapause (Lauterer, , ; Hodkinson, ; Horton et al ., ) until environmental conditions are more suitable. In particular, reproductive diapause in late autumn and early winter is well described in two species of pear psylla: C. pyricola (Krysan & Higbee, ) and C. pyri (Kapatos & Stratopoulou, ). We questioned whether this phenomenon also occurs in C. bidens in a southern Mediterranean climate.…”

“…The summerforms are small and light‐coloured, whereas the winterforms are larger and dark (Oldfield, ). Cacopsylla pyricola and C. pyri exhibit reproductive diapause during the winter months, as characterized by a lack of mating and immature ovaries (Krysan & Higbee, ; Kapatos & Stratopoulou, ). These seasonal changes fit well with the phenology of their deciduous host plant.…”

Diversity, biology, and management of the pear psyllids: a global look

“…In contrast, longevity of summerform C. pyricola reared under laboratory conditions is ∼50–80 days at moderate temperatures (21–24 °C) or briefer at warmer temperatures (McMullen and Jong 1977). Life span in the field is even shorter, ranging between 16–32 days for C. bidens in Israel (Swirski 1953), 14–28 days for C. pyri in Greece (Kapatos and Stratopoulou 1996), and 18–26 days for C. chinensis in China (Wei et al 2020).…”

“…Field estimates of fecundity are noticeably lower than estimates from laboratory trials. Lifetime egg production under field conditions has been estimated for summerform C. bidens (50–170 eggs: Swirski 1953) and C. pyricola (70–190 eggs: Georgala 1956, McMullen and Jong 1972); and, winterform C. pyricola (200 eggs: Georgala 1956) and C. pyri (135–150 eggs: Kapatos and Stratopoulou 1996). Field data are available for 1 Asian species, C. chinensis , estimated at 25–70 eggs per summerform female (Wei et al 2020).…”