Data from: Genotype-by-environment interactions for seminal fluid expression and sperm competitive ability

Sperm competition commonly occurs whenever females mate multiply, leading
to variation in male paternity success. This can be due to variation in
the various traits that might affect sperm competitive ability, which
itself depends on both genetic and environmental factors, as well as on
genotype-by-environment interactions (GEI). Seminal fluid is a major
component of the male ejaculate that is often expected to mediate sperm
competition, where different genotypes can differ in their seminal fluid
expression as a response to different level of sperm competition (i.e.,
exhibit GEI). We therefore here focussed on testing for GEI in expression
of two recently identified seminal fluid transcripts, suckless-1 and
suckless-2, which potentially modulate sperm competitive ability in the
simultaneously hermaphroditic flatworm Macrostomum lignano via their
effects on manipulating post-mating partner behaviour and ultimately the
fate of transferred ejaculates. In addition, we sought to test for GEI in
sperm competitive ability in a standardised sperm competition (P1
& P2) assay, to investigate the relationship between natural
variation in the expression of these seminal fluid transcripts generated
through GEI and relative paternity success. We found GEI for the
expression level of suckless-1 and suckless-2, as well as for sperm
competitive ability. Moreover, we found a positive relation between the
expression of suckless-1 and relative paternity success (P1). This
suggests that natural variation in the expression of this seminal fluid
transcript indeed can influence sperm competition outcomes in M. lignano.

当雌性多次交配时，精子竞争普遍发生，这会导致雄性父权成功率的差异。这可能源于影响精子竞争能力的多种性状的变异，而精子竞争能力本身既依赖于遗传和环境因素，也依赖于基因型-环境互作（GEI）。精浆（seminal fluid）是雄性射精物（ejaculate）的主要成分，通常被认为介导精子竞争——不同基因型在应对不同水平的精子竞争时，其精浆表达可能存在差异（即表现出GEI）。因此，我们在此重点测试两种近期鉴定的精浆转录本（transcripts）suckless-1和suckless-2的表达是否存在GEI——这些转录本可能通过调控交配后伴侣的行为，最终影响转移射精物的命运，从而调节雌雄同体扁形动物Macrostomum lignano的精子竞争能力。此外，我们试图在标准化精子竞争实验（P1 & P2）中测试精子竞争能力是否存在GEI，以探究由GEI产生的这些精浆转录本表达的自然变异与相对父权成功率之间的关系。我们发现suckless-1和suckless-2的表达水平以及精子竞争能力均存在GEI。此外，我们发现suckless-1的表达与相对父权成功率（P1）呈正相关。这表明，该精浆转录本表达的自然变异确实能够影响M. lignano的精子竞争结果。