Assessment of hybrid vigor between flightless lines to restore survival and reproductive characteristics in the ladybird beetle Harmonia axyridis

Abstract

The effectiveness of hybrid vigor, which can counteract deleterious effects of inbreeding in flightless Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was investigated. First, we performed the reciprocal cross between two isofemale lines and compared survival and reproductive characteristics between isofemale and hybrid lines under laboratory conditions. The survival of one of the hybrid lines was significantly higher than that of the two isofemale lines. Early fecundity tended to be higher in the two hybrid lines than in the two isofemale lines. Second, we compared the effectiveness of control of Aphis gossypii Glover (Homoptera: Aphididae) between isofemale and hybrid lines by release experiments in greenhouses. The number of A. gossypii was suppressed in treatments in which two hybrid lines were released compared with those in which two isofemale lines were released. These results suggest that hybrid vigor is effective as a method for assuring the quality of flightless H. axyridis.

Inheritance of diapause regulation in the multicoloured Asian ladybird Harmonia axyridis (Coleoptera: Coccinellidae)

“…Our study revealed a high level of heterogeneity in the invasive population. High genetic diversity is commonly considered an important prerequisite for a biological invasion by the multicoloured Asian ladybird (Facon et al, 2008Lombaert et al, 2010;Turgeon et al, 2011;Seko et al, 2012). Moreover, meta-analysis of the data on various invaders suggests that high levels of genotypic diversity in founder groups increase establishment success (Forsman, 2014), although there are exceptions to this rule (Handley et al, 2011).…”

“…The results of this study are not only of theoretical but also of practical importance. Several authors note that hybridization between individuals from different native, invasive and mass-reared populations of H. axyridis has had an effect on the worldwide spread of this species (Facon et al, 2008Lombaert et al, 2010;Handley et al, 2011;Turgeon et al, 2011;Seko et al, 2012). Thus, the mode of inheritance of diapause regulation could be a signifi cant factor in the further spread of the multicoulored Asian ladybird.…”

Production of Coleopteran Predators

“…inbreeding) in a population of insects over many generations can have detrimental effects on the health of a colony and on the performance of individuals released in the field (Mackauer, 1976;Roush and Hopper, 1995). Inbreeding may reduce the fitness of coccinellids such as A. bipunctata, C. maculata, H. axyridis, and Propylea quatuordecimpunctata (L.) (Kidd, 1993;Hurst et al, 1996;Morjan et al, 1999;Facon et al, 2011;Seko et al, 2012). Methods to reduce or prevent the deterioration of colonies may include manipulative breeding between hybrids to restore normal growth, survival, and reproductive capacities of populations in culture.…”

Lack of phenotypic variation despite population structure in larval utilization of pea aphids by populations of the lady beetle Hippodamia convergens

“…Hippodamia convergens within the designated Western and Eastern populations in the United States have likely adapted to varying natural conditions, pathogens and parasitoids cycles. Augmenting populations by bringing Western and Eastern populations together to create hybrids can also potentially increase the fitness of the hybrid population, a phenomenon that is commonly described as ‘hybrid vigor’ (Seko et al, 2012).…”