Mating Biology of Austromusotima camptozonale (Lepidoptera: Crambidae), a Potential Biological Control Agent of Old World Climbing Fern, Lygodium microphyllum (Schizaeaceae)

Anthony J. Boughton, Judy Wu, Robert W. Pemberton

Abstract


Austromusotima camptozonale (Hampson) is under investigation as a potential biological control agent of Old World climbing fern, Lygodium microphyllum (Cav.) R. Br., which is a serious invasive weed in southern Florida. Studies were conducted to investigate aspects of the mating biology of A. camptozonale with a view to improving field colonization efforts. A laboratory colony of A. camptozonale had a female-biased sex ratio of 1:1.3 male:female, with females emerging slightly earlier than males. The majority of female moths mated only once, even when they were confined with multiple males for several nights. Sex ratio had a significant effect on the percentage of females that were mated, with higher percentages of females mated at high male sex ratios. However sex ratio had no effect on the number of times individual females mated. Larval production was significantly higher in colony cages with high male sex ratios, and this was likely due to the higher percentages of females that were mated in these cages. Data suggest that A. camptozonale females are likely to be functionally monandrous under field conditions. Females produced a lifetime average of 61.2 ± 9.7 larvae, and were short-lived, surviving an average of 5.7 ± 0.5 d. Females began oviposition on the first night after mating and continued until the day of their death. However 90% of eggs were deposited between the first and third night after mating. Due to the short lifespan of female moths, adults may not be the best life stage for field release in a biological control program, owing to likely disruption of critical mating and oviposition activities. Elevating the ratio of males in colony mating cages is a strategy for maximizing female reproductive output.

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