Investigation of the biology and cross-breeding of populations of Pareuchaetes insulata (Lepidoptera : Arctiidae) and the implications for the biological control of Chromolaena odorata (Asteraceae) in South Africa.
Abstract
Larvae of Pareuchaetes insulata were released in South Africa for the biological control of the invasive weed Chromolaena odorata. Pareuchaetes insulata has proved to be a difficult agent to establish in the field in South Africa, for various possible reasons. Populations collected from Florida and Jamaica (their aboriginal home) were released separately at several sites each in South Africa, but only one population (Florida) was definitely established. It is possible that adults from this established population interbred with adults from the Jamaican population released at nearby sites.
The aims of this study were to determine whether there were any differences in biology between the two populations and whether hybridization affected the fitness of either. Trials involved: (i) pure-breeding of both Florida (F) and Jamaica (J) populations; (ii) cross-breeding of the two populations and; (iii) back-crossing of the hybrids with the parent populations. The fitness of these populations was determined by measuring adult longevity and fecundity, egg viability, and larval development and survival rates.
The F population was superior to the J population in most of parameters measured, including fecundity. Hybridization of these populations reduced the fitness of the F population. It is unknown whether these differences in fitness reflect differences in their native regions, laboratory cultures or response to South African C. odorata. It appears that different populations of P. insulata have different levels of fitness, and that hybridization negatively affects the fitness of stronger populations. The lower fitness of the J population may have reduced its likelihood of establishing successfully, and even reduced the fitness of the established F population where the populations came into contact. These results caution that the possible consequences of mixing different genotypes of a biocontrol agent species should be properly investigated prior to their release in the same country.
Collections
Related items
Showing items related by title, author, creator and subject.
-
Development of fungal biological control of four agriculturally important pests, Sitophilus oryzae, Trialeurodes vaporariorum, Planococcus ficus and Eldana saccharina, in South Africa.
Chambers, Craig Brian. (2005)The use of entomopathogenic fungi to control agriculturally important pests, both in greenhouses and in the field, has been demonstrated by various authors for a number of years. This has been brought about by the ... -
The utility of Brachylaena discolor as a bioindicator of air pollution within selected industrial areas in KwaZulu-Natal.
Areington, Candyce Ann. (2016)The negative impacts of air pollution have made monitoring of air quality increasingly important. This is primarily true for industrial areas such as the South Durban Basin (SDB) within the eThekwini Municipal Area (EMA), ... -
Aspects influencing the release and establishment of the flowerbud weevil, Anthonomus santacruzi Hustache (Coleoptera : Curculionidae), a biological control agent for Solanum mauritianum scopoli (Solanaceae) in South Africa.
Hakizimana, Seth. (2011)Solanum mauritianum (bugweed, woolly nightshade) is a perennial tree native to South America that has invaded many countries including South Africa and New Zealand. In South Africa, after 143 years of naturalization, the ...