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ARS Home » Southeast Area » Fort Lauderdale, Florida » Invasive Plant Research Laboratory » Research » Publications at this Location » Publication #205915
Title: MATING BIOLOGY OF AUSTROMUSOTIMA CAMPTOZONALE (LEPIDOPTERA: CRAMBIDAE) - A POTENTIAL BIOLOGICAL CONTROL AGENT OF OLD WORLD CLIMBING FERN, LYGODIUM MICROPHYLLUM (SCHIZAEACEAE)

Author
item Boughton, Anthony
item WU, JUDY - SCA-ARS, FT. LAUDERDALE
item Pemberton, Robert

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2007
Publication Date: 9/30/2007
Citation: Boughton, A.J., Wu, J., & Pemberton, R.W. (2007) Mating Biology of Austromusotima camptozonale (Lepidoptera: Crambidae) - a Potential Biological Control Agent of Old World Climbing Fern, Lygodium microphyllum (Schizaeaceae). Florida Entomologist, 90, 509-517.

Interpretive Summary: Old World Climbing fern, Lygodium microphyllum is native to S.E. Asia and Australia, and is a serious invasive weed in southern Florida. Austromusotima camptozonale is a moth that is native to S.E. Asia and Australia, whose caterpillars defoliate L. microphyllum, and in so doing reduce the fern's capacity for growth and reproduction. A. camptozonale is under consideration as a biological control agent for use in managing L. microphyllum. In an effort to better understand the biology of A. camptozonale and improve future efforts to establish field populations of this moth, studies were conducted to investigate aspects of the reproductive biology of A. camptozonale. Results showed that A. camptozonale has a female-biased sex ratio (1:1.3 male:female), and that moths emerged from pupae over a period of about seven days. Significantly higher percentages of female moths were mated in laboratory mating cages that had high male to female sex ratios. However cage sex ratio did not influence the number of times that individual female moths mated, and the vast majority of females mated only once. Mean production of caterpillar offspring per cage was significantly higher in cages with high male to female sex ratios, but this was likely due to increased percentages of female moths being mated, rather than due to increased egg laying by individual females. It is likely that under field conditions, A. camptozonale females will mate only once during their lifetime. Female moths produced a lifetime average of 61.2 caterpillars, and were short-lived, surviving an average of 5.7 days. 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.

Technical 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 tending to emerge slightly earlier than males. The majority of female moths mated only once, even when they were confined with multiple males for several nights. Cage 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 individuals 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 days. 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.