Submitted to: The Canadian Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 20, 2005
Publication Date: May 1, 2005
Citation: Horton, D.R., Lewis, T.M., Neven, L.G. 2005. Ovarian development and lipid reserves are affected by mating delays in three species of anthocoris (heteroptera: anthocoridae). The Canadian Entomologist. 137(3):328-336. Interpretive Summary: Predatory bugs in the Family Anthocoridae are unusual in the Insecta in that mating is required to prompt full development of the ovaries within the female. We showed that an absence of mating in three species of anthocorid bugs led to an increase in energy reserves allocated to non-reproductive tissues, suggesting that egg maturation costs these insects energy. Delays in mating led to delays in egg-laying, due to the absence of egg development in unmated bugs. The three species differed in the amount of time required for females to begin egglaying following mating, with a range noted of 3 to 8 days, depending upon species. Our results show that care must be taken in defining certain life history events in these insects, as delays in mating had substantial effects on timing of egglaying.
Technical Abstract: Mating was necessary to prompt ovarian maturation and egg-laying in Anthocoris tomentosus , A. whitei, and A. nemoralis. Lack of mating led to higher lipid reserves allocated to somatic tissues than noted in mated bugs, suggesting that there was a trade-off between allocation of resources to eggs and to somatic reserves. The species differed in rate of oocyte development by unmated females. Unmated females of A. nemoralis and A. whitei exhibited an increase in length of the terminal oocyte within 2 days of eclosion. In contrast, oocyte length in unmated females of A. tomentosus was the same as that in newly eclosed females, irrespective of female age. Mated A. nemoralis and A. whitei had larger oocytes than unmated females within 2 days of mating. Mated A. tomentosus had larger oocytes than unmated females by 4 days following mating. Embryos were visible in the eggs of mated A. nemoralis and A. whitei by 2-3 days following mating, compared to 5 days for A. tomentosus. Mature eggs having egg caps were visible by 3, 4, and 6 days after mating for A. nemoralis, A. whitei, and A. tomentosus, respectively. Delays in mating resulted in delays in egg-laying. In A. tomentosus, onset of egg-laying occurred 8 days following mating, whether mating occurred on the day of eclosion, at 3 days of age, or at 10 days of age. In contrast, A. nemoralis females required fewer days following mating to begin egg-laying if females were mated at 3 or 10 days of age than if mated on the day of eclosion. A similar effect was noted for A. whitei mated at 10 days of age. Time required for A. whitei and A. nemoralis to begin egg-laying following mating was 3-5 days, depending upon age of the female when she was mated. These results indicate that care must be taken in defining duration of the preoviposition period in these insects.