Population differences and domestication effects on mating and remating frequencies in Queensland fruit fly

Abstract

Females of many insect species are unreceptive to remating for a period following their first mating. This inhibitory effect may be mediated by either the female or her first mate, or both, and often reflects the complex interplay of reproductive strategies between the sexes. Natural variation in remating inhibition and how this phenotype responds to captive breeding are largely unexplored in insects, including many pest species. We investigated genetic variation in remating propensity in the Queensland fruit fly, Bactrocera tryoni, using strains differing in source locality and degree of domestication. We found up to threefold inherited variation between strains from different localities in the level of intra-strain remating inhibition. The level of inhibition also declined significantly during domestication, which implied the existence of genetic variation for this trait within the starting populations as well. Inter-strain mating and remating trials showed that the strain differences were mainly due to the genotypes of the female and, to a lesser extent, the second male, with little effect of the initial male genotype. Implications for our understanding of fruit fly reproductive biology and population genetics and the design of Sterile Insect Technique pest management programs are discussed.

Multi-locus genotyping of stored sperm reveals female remating rates in wild populations of the Queensland fruit fly

“…Polyandry level was significantly higher in the NSW collection than the QLD collection (NSW = 80.0 %, N = 25; QLD = 26.1 %, N = 23; χ 2 = 14.02; DF = 1; P < 0.001) ( Figure 1 ). While field remating rate for the QLD collection was generally on par with laboratory estimates for three Qfly populations at their early stages of domestication ( Ahmed et al., 2022 ) and field estimates from other tephritids including C. capitata ( Bonizzoni et al. , 2002 ; Kraaijeveld et al.…”

“…Natural variation in remating propensity is likely to be influenced by a myriad of genetic, physiological, and environmental factors. Genetic background, especially the genotype of the females, has been shown to influence remating frequencies between populations in Qfly ( Ahmed et al., 2022 ) and C. capitata ( Saul and McCombs, 1993 ). In addition, demography and season (including major weather events) may also contribute to remating propensity in the field.…”

“…Such knowledge can inform decisions of release rate and release intervals of sterile males. Female remating in Qfly under laboratory conditions has been reported ( Ahmed et al., 2022 ; Harmer et al., 2006 ; Radhakrishnan and Taylor, 2008 ) but the occurrence and rate of remating in wild populations remain unknown.…”

Postcopulatory Behavior of Tephritid Flies

“…Importantly, in Bactrocera latifrons, when females were artificially selected across 12 generations to mate with sterile males, this did not result in higher remating rates (84). Nevertheless, domestication, such as that which occurs for colonies in the SIT, does increase remating, but this depends more on female rather than male genotypes (14,93).…”

Genetic variation for rectal gland volatiles among recently collected isofemale lines and a domesticated strain of Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)

“…Table 1 summarises the collection details for these populations. Further information on them is available in Popa-Ba ´ez et al [70] and Ahmed et al [111].…”