Submitted to: Pan-Pacific Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2001
Publication Date: March 20, 2002
Citation: Horton, D.R., Lewis, T.M., Hinojosa, T.L. 2002. Copulation duration in three species of Anthocoris (Heteroptera: Anthocoridae) at different temperatures and effects on insemination and ovarian development. Pan-Pacific Entomologist. 73:43-55. Interpretive Summary: Despite their importance as biological control agents, the basic biology of predatory bugs within the genus Anthocoris is poorly described. Preliminary observations suggested that species in this genus differ substantially in aspects of reproductive biology. We compared mating durations in 3 species of Anthocoris (A. tomentosus, A. whitei, and A. nemoralis) that inhabit pear orchards in the western U.S. & determined whether duration affected probability of sperm transfer and egg maturation. Mean mating duration differed among the three species, being very short in one species (14 min) & very long in another species (89 minutes); the third species showed duration of intermediate length (40 minutes). For each species, probability of sperm transfer & egg maturation increased with increasing duration of mating. Probability of sperm transfer was often larger than that of egg maturation, suggesting that sperm transfer did not always prompt egg development in some females of these two species. Temperature was shown to affect duration & probability of insemination. This study provides new information on the reproductive biology of species in this important taxon of insects.
Technical Abstract: We compared mean duration of copulation among three species of predatory bugs in the genus Anthocoris: A. tomentosus P¿ricart, A. whitei Reuter, and A. nemoralis (Fabricius). Copulation duration was longest in A. whitei (mean = 89.3 min), of intermediate length in A. tomentosus (mean = 40.0 min), and shortest in A. nemoralis (mean = 14.1 min). By interrupting mating pairs we showed that probability of insemination increased with increasing duration of copulation. In the Anthocoridae, eggs are fertilized in the ovaries before the chorion is deposited, and fertilization is necessary to prompt complete development. Therefore, as with insemination probabilities, probability of ovarian maturation also increased with increasing copulation duration. Probability of insemination was often higher than probability of ovarian maturation, suggesting that some females that were successfully inseminated nonetheless failed to develop eggs. Size of the membranous sperm reservoir in the female increased with increasing duration of copulation. Results suggest that males transferred seminal products for most of the copulation period. Cooler temperatures resulted in prolonged durations.