The 56 Conference of the Zoological Society of Israel
Relatedness level between mating organisms is considered a key factor affecting mate selection. The reproducing organism may select to mate with either a distant or a closely related member of the same species, or choice may shift in successive generations. While Inbreeding is generally avoided to prevent homozygosity, it is predominantly practiced in haplo-diploid organism where the depression is frequently avoided due to purging of deleterious genes. Inbreeding is occasional followed by outbreeding to prevent lethal genes' effect. Previous studies of some inbred haplo-diploid species showed early and temporary fitness depression under outbreeding. Long-term effects of outbreeding in a regularly inbreeding species have rarely been studied. In our study we used the haplo-diploid beetle Coccotrypes dactyliperda (Scolytidae: Xyloborinae) to study mate preferences and its immediate and long-term effect on fitness of different levels of inbreeding in two populations distant from one another. Breeding lines were established with three level of relatedness: Extreme Inbreed - Female mated with siblings; Inbreed - Females mated with same line males; Outbreeding – outbreeding with different population on odd generations, and inbreeding on even number generations. The study was extended over ten generations unless fitness depression was observed. Fitness was evaluated by progeny/clutch size. Initial finding suggest a relatively early outbreeding depression in both populations and delayed inbreeding depression in only one of the populations. Fitness enhancement rather than the expected fitness depression was observed in the extreme inbreeding lines. Our findings are complying with the Coccotrypes dactyliperda species life history. Extreme-Inbreeding through sibling mating predominates until the date seed is consumed, followed by offspring's dispersal. Inbreeding may occur when dispersing females may enter and share the seed. Outbreeding between different population rarely occurs and is generally followed by Extreme Inbreeding after the seed had been habituated.
The 56 Conference of the Zoological Society of Israel
Relatedness level between mating organisms is considered a key factor affecting mate selection. The reproducing organism may select to mate with either a distant or a closely related member of the same species, or choice may shift in successive generations. While Inbreeding is generally avoided to prevent homozygosity, it is predominantly practiced in haplo-diploid organism where the depression is frequently avoided due to purging of deleterious genes. Inbreeding is occasional followed by outbreeding to prevent lethal genes' effect. Previous studies of some inbred haplo-diploid species showed early and temporary fitness depression under outbreeding. Long-term effects of outbreeding in a regularly inbreeding species have rarely been studied. In our study we used the haplo-diploid beetle Coccotrypes dactyliperda (Scolytidae: Xyloborinae) to study mate preferences and its immediate and long-term effect on fitness of different levels of inbreeding in two populations distant from one another. Breeding lines were established with three level of relatedness: Extreme Inbreed - Female mated with siblings; Inbreed - Females mated with same line males; Outbreeding – outbreeding with different population on odd generations, and inbreeding on even number generations. The study was extended over ten generations unless fitness depression was observed. Fitness was evaluated by progeny/clutch size. Initial finding suggest a relatively early outbreeding depression in both populations and delayed inbreeding depression in only one of the populations. Fitness enhancement rather than the expected fitness depression was observed in the extreme inbreeding lines. Our findings are complying with the Coccotrypes dactyliperda species life history. Extreme-Inbreeding through sibling mating predominates until the date seed is consumed, followed by offspring's dispersal. Inbreeding may occur when dispersing females may enter and share the seed. Outbreeding between different population rarely occurs and is generally followed by Extreme Inbreeding after the seed had been habituated.