Data from: Parental sublethal insecticide exposure prolongs mating response and decreases reproductive output in offspring

1.Insecticide usage is steadily increasing, implying an ongoing threat of
sublethal exposure for non‐target organisms in habitats close to farmland.
The exposure to low insecticide doses is often associated with a fitness
decline in affected organisms. 2. We determined the effects of exposure to
the sublethal pyrethroid lambda‐cyhalothrin, at a concentration 20 times
lower than the LC50, on the cuticle surface profile containing mating
cues, the mating and aggression behaviour and fitness consequences for a
beetle species (Phaedon cochleariae Fabricius), which faces agropollutants
when occurring close to farmland. Traits were investigated in the
insecticide‐exposed parental generation, and carry‐over effects into their
unexposed offspring were studied. 3. In both the parental and the
offspring generation, the chemical surface profile was unaffected by the
insecticide exposure. Nevertheless, insecticide exposure and carry‐over
effects decreased male mating acceptance of females in no‐choice
situations. A reduced acceptance of insecticide‐exposed females may be
related to changes in specific chemical surface cues, because males
attempted to mate more readily with dummies treated with surface extracts
of control females than of insecticide‐exposed females. Moreover, females
became more aggressive in dual‐choice situations towards other females in
the presence of an insecticide‐exposed compared to an unexposed male,
potentially due to neuronal dysfunctions. Thus, both intersexual
(chemical) communication during mating and intrasexual communication were
altered in response to insecticide exposure. 4. Insecticide‐exposed
parents and their offspring suffered from a decreased reproductive output,
likely due to direct toxic effects or constraints induced by
detoxification processes. The carry‐over effects might be mediated by a
parental insecticide transfer or insecticide‐induced heritable epigenetic
changes involved in detoxification processes. 5. Synthesis and
applications. This study demonstrates that sublethal insecticide exposure
can have far‐reaching consequences on (non‐target) herbivores. These
results have implications for population dynamics and, ultimately, for
ecological communities, as insects are highly important members of food
chains. Therefore, long‐term effects of short‐term insecticide exposure
should be considered in the evaluation of pesticides and the discussion
about pesticide usage in agriculture.