In some species, populations with few founding individuals can be resilient to extreme inbreeding. Inbreeding seems to be the norm in the common bed bug, Cimex lectularius, a flightless insect that, nevertheless, can reach large deme sizes and persist successfully. However, bed bugs can also be dispersed passively by humans, exposing inbred populations to gene flow from genetically distant populations. The introduction of genetic variation through this outbreeding could lead to increased fitness (heterosis) or be costly by causing a loss of local adaptation or exposing genetic incompatibility between populations (outbreeding depression). Here, we addressed how inbreeding within demes and outbreeding between distant populations impact fitness over two generations in this re-emerging public health pest. We compared fitness traits of families that were inbred (mimicking reproduction following a founder event) or outbred (mimicking reproduction following a gene flow event). We found that outbreeding led to increased starvation resistance compared to inbred families, but this benefit was lost after two generations of outbreeding. No other fitness benefits of outbreeding were observed in either generation, including no differences in fecundity between the two treatments. Resilience to inbreeding is likely to result from the history of small founder events in the bed bug. Outbreeding benefits may only be detectable under stress and when heterozygosity is maximized without disruption of coadaptation. We discuss the consequences of these results both in terms of inbreeding and outbreeding in populations with genetic and spatial structuring, as well as for the recent resurgence of bed bug populations.
Fecundity measures for two generations of inbreeding/outbreeding in the common bed bug
This file contains fecundity measures for two generations of inbreeding and outbreeding in the common bed bug. The file gives multiple measures per female. line = focal female, female/male.pop and .line = origin of parents as outlined in manuscript. Abbreviated names: S1 = Lab stock, 4S = mixed stock, F4 = field UK, K12 = field Kenya. Parent pop and line information are not given in outbred g2 individuals as they are no longer meaningful here (see manuscript) Parents size is given in (f.pronotum/m.pronotum), week = time point where eggs were collected, fertile = Number of fertile eggs, infertile = Number of Infertile eggs, total = Total number of eggs. Egg.size is given in mm and measured as length of egg.
g1.g2.analyse.combine.csv
Offspring survival after starvation after one generation of inbreeding and outbreeding in the common bed bug
This file contains survival of adult offspring after one generation of inbreeding and outbreeding in the common bed bug. Individuals were starved and their survival recorded. line = focal mother, female/male.pop and .line = origin of parents as outlined in manuscript. Abbreviated names: S1 = Lab stock, 4S = mixed stock, F4 = field UK, K12 = field Kenya. Parents size is given in (f.pronotum/m.pronotum), sex = gender of offspring, event: 1 = death, 0 = survived, time = day of sampling. Sampling was stopped at day 70.
g1.adult.survival.final.csv
Offspring survival after starvation after two generations of inbreeding and outbreeding in the common bed bug
This file contains survival of adult offspring after two generations of inbreeding and outbreeding in the common bed bug. line = focal mother, female/male.pop and .line = origin of parents as outlined in manuscript. Abbreviated names: S1 = Lab stock, 4S = mixed stock, F4 = field UK, K12 = field Kenya. Parent pop and line information are not given in outbred individuals as they are no longer meaningful here (see manuscript). Parents size is given in (f.pronotum/m.pronotum), sex = gender of offspring, event = 1 = death, 0 = survived, time = day of sampling. Sampling was stopped at day 70.
g2.adult.survival.final.csv
Offspring body size after two generations of inbreeding and outbreeding in the common bed bug
This file contains body size measures (pronotum width) for adult offspring after one or two generations of inbreeding and outbreeding in the common bed bug. The file gives multiple measures per female. line = focal female (mother), female/male.pop and .line = origin of parents as outlined in manuscript. Abbreviated names: S1 = Lab stock, 4S = mixed stock, F4 = field UK, K12 = field Kenya. Parent pop and line information are not given in outbred g2 individuals as they are no longer meaningful here (see manuscript) Parents size is given in (f.pronotum/m.pronotum), female.off = female offspring size, male.off = male offspring size. There are multiple offspring measured for each mother.
g1.g2.analyse.bodysize.csv