JUVENILE-HORMONE IN EARWIGS - ROLES IN OOGENESIS, MATING, AND MATERNAL BEHAVIORS

The role of juvenile hormone (IH) in courtship, mating, maternal behav ior, and the ovarian cycle was studied in the ring-legged earwig, Eubo rellia annulipes (Lucas). The single, median corpus allatum makes and secretes JH III. JH III production was low in newly eclosed adult fema les, increasing as oocytes developed, maximal at about the time of ovi position, and low again in brooding females. Application of 35 or 122 mu g JH III to newly eclosed females hastened the onset of courtship b ehavior, but had no effect on the age at which females first mated nor on the duration of mating, though the trend is toward advanced onset. Hormone treatment advanced the age of first oviposition and reduced c lutch size and the proportion of eggs hatching but did not affect the interval from oviposition of the first clutch to oviposition of the se cond clutch, nor the size and proportion hatching of the second clutch . Acetone treatment and treatment with 6 mu g JH III did not affect th ese parameters. Application of 50 mu g JH III to females on the day of oviposition shortened the duration of maternal care and advanced the onset of the second gonadotropic cycle, compared with that of acetone- treated and precocene Ii-treated females. The duration of maternal car e was positively correlated with the proportion of eggs hatching. JH t iter analysis confirmed IH III to be the predominant hormone in this s pecies and clearly demonstrated the absence of other homologues. This work also confirmed our hypothesis that intermediate to high levels of JH are associated with oocyte growth, mating, and cessation of matern al care; low levels of JH are associated with the period of maternal b ehavior and slow ovarian development. We are currently investigating f actors which might regulate corpus allatum activity during the reprodu ctive cycle and the subsequent period of maternal care. (C) 1997 Wiley -Liss, Inc.