Maternal Care in the Neotropical Harvestman Bourguyia Albiornata (Arachnida: Opiliones): Oviposition Site Selection and Egg Protection

Abstract

SummaryFemales of the harvestman Bourguyia albiornata oviposit almost exclusively inside the tube formed by the curled leaves of the bromeliad Aechmea nudicaulis. Oviposition is not correlated with rainfall or with temperature, but is negatively correlated with the number of individuals of A. nudicaulis emitting owers. Because the in orescence stalk occupies the tube of leaves of owering bromeliads, oviposition site is not available for ovigerous females. During one year, 83.6% of the females produced only one egg-batch and the remaining produced two or three batches. The mean number of eggs per batch along successive reproductive events decreased signi cantly. A eld experiment in which females were removed from the nest bromeliad showed that less than 7% of the unprotected eggs survived beyond two weeks. In a control in which females were maintained over the eggs, predators attacked only one egg-batch. Ants were the most important egg predators, and at the study site at least 20 species nest and/or forage in A. nudicaulis. Intense predation on eggs by generalist predators may be an important pressure promoting parental care in Neotropical harvestmen.

Oviposition site selection by the bromeliad-dweller harvestman Bourguyia hamata (Arachnida: Opiliones)

“…Machado and Oliveira (2002) showed that B. hamata females oviposit almost exclusively inside the epiphytic bromeliad Aechmea nudicaulis at Cardoso Island, southeastern Brazil-even though this species represents only approximately 10% of the epiphytic bromeliads in the study area. Aechmea nudicaulis is a bromeliad with long curled leaves forming a tubular rosette that accumulates water (Wanderley and Mollo 1992;see also Fig.…”

“…Each female found inside the individuals of A. nudicaulis was captured and classified according to her reproductive condition as non-reproductive, ovigerous (recognized through the enlarged abdomen with distended intersegmental membranes), or guarding (when taking care of eggs or nymphs). Each female received an individual mark with enamel paint and was released at the same bromeliad where she was found (following Machado and Oliveira 2002).…”

“…Aechmea nudicaulis is a bromeliad with long curled leaves forming a tubular rosette that accumulates water (Wanderley and Mollo 1992;see also Fig. 1a in Machado and Oliveira 2002). Females of B. hamata lay their eggs inside the rosette and guard the clutch until the hatching and dispersal of all nymphs, which lasts from 35 to 43 days.…”

“…Females of B. hamata lay their eggs inside the rosette and guard the clutch until the hatching and dispersal of all nymphs, which lasts from 35 to 43 days. Maternal care has a crucial protective role for egg survival, because unprotected clutches can be entirely consumed by ants and/or conspecifics in a few hours (Machado and Oliveira 2002).…”

Diversity and Habitat Use of Neotropical Harvestmen (Arachnida: Opiliones) in a Costa Rican Rainforest

“…For example, individuals of some gonyleptid species seek diurnal refuge in caves and only leave at night to forage [49,50]. Several species inhabit leaf cutter ant nests [51], while others occupy bromeliads [52] or rely on bromeliads for reproduction [53]. Individuals of some temperate sclerosomatid species are known to make vertical migrations-climbing on trees during the day and descending at dusk to forage on or near the ground [6,17,18].…”