Environment, Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia.
Applied BioSciences, Macquarie University, North Ryde, NSW, Australia.
J Insect Sci. 2024 May 1;24(3). doi: 10.1093/jisesa/ieae066.
Bactrocera tryoni (Froggatt) and Bactrocera neohumeralis (Hardy) are sibling fruit fly species that are sympatric over much of their ranges. Premating isolation of these close relatives is thought to be maintained in part by allochrony-mating activity in B. tryoni peaks at dusk, whereas in B. neohumeralis, it peaks earlier in the day. To ascertain whether differences in pheromone composition may also contribute to premating isolation between them, this study used solid-phase microextraction and gas chromatography-mass spectrometry to characterize the rectal gland volatiles of a recently collected and a more domesticated strain of each species. These glands are typical production sites and reservoirs of pheromones in bactrocerans. A total of 120 peaks were detected and 50 were identified. Differences were found in the composition of the rectal gland emissions between the sexes, species, and recently collected versus domesticated strains of each species. The compositional variation included several presence/absence and many quantitative differences. Species and strain differences in males included several relatively small alcohols, esters, and aliphatic amides. Species and strain differences in females also included some of the amides but additionally involved many fatty acid esters and 3 spiroacetals. While the strain differences indicate there is also heritable variation in rectal gland emissions within each species, the species differences imply that compositional differences in pheromones emitted from rectal glands could contribute to the premating isolation between B. tryoni and B. neohumeralis. The changes during domestication could also have significant implications for the efficacy of Sterile Insect Technique control programs.
地中海实蝇（Bactrocera tryoni (Froggatt)）和新菠萝果实蝇（Bactrocera neohumeralis (Hardy）是近缘种，在其大部分分布范围内存在同域分布现象。这些近缘种之间的交配前隔离被认为部分是由异时性维持的，即在 B. tryoni 中交配活动的高峰期出现在黄昏，而在 B. neohumeralis 中则出现在白天更早的时候。为了确定信息素组成的差异是否也有助于它们之间的交配前隔离，本研究使用固相微萃取和气相色谱-质谱联用技术对最近收集的和更驯化的每个物种的直肠腺挥发物进行了特征描述。这些腺体是双翅目昆虫中典型的信息素产生部位和储存库。共检测到 120 个峰，鉴定出 50 个峰。在性别、物种以及每个物种的最近收集和驯化种群之间的直肠腺排放物组成方面发现了差异。组成变化包括存在/不存在和许多定量差异。雄性之间的物种和种群差异包括几种相对较小的醇、酯和脂肪族酰胺。雌性之间的物种和种群差异也包括一些酰胺，但另外还涉及许多脂肪酸酯和 3 个螺缩醛。虽然种群差异表明每个物种的直肠腺排放物中也存在可遗传变异，但物种差异意味着从直肠腺中释放的信息素的组成差异可能有助于 B. tryoni 和 B. neohumeralis 之间的交配前隔离。驯化过程中的变化也可能对不育昆虫技术控制计划的效果产生重大影响。
