Lea C. Böttinger, Frederic Hüftlein, Johannes Stökl
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引用次数: 3
Abstract
A major hypothesis for the evolution of chemical signals is that pheromones arise from non-communicative precursor compounds. However, data supporting this hypothesis are rare, primarily because the original functions of the antecedent compounds often have been lost. A notable exception, however, is the parasitoid wasp species Leptopilina heterotoma, whose compound (?)-iridomyrmecin is used as a defensive secretion, a cue for females to avoid competition with con- and hetero-specific females, and as the primary component of the females’ sex pheromone. To better understand the evolution of sex pheromones from defensive compounds, we examined the chemical ecology of L. pacifica, the sister species of L. heterotoma. Here, we show that L. pacifica also produces a defensive secretion containing a species-specific mixture of mostly iridoid compounds. However, the composition of the secretion is more complex than in L. heterotoma, and iridomyrmecin is only a minor component. Moreover, in contrast to L. heterotoma, conspecific female competitors were not avoided by female subjects, and a role of the iridoids in the female sex pheromone of L. pacifica can be excluded, as only the females’ cuticular hydrocarbons (CHCs) resulted in the elicitation of courtship by males. Although closely related, the two sister species show substantial differences in the use of the defensive secretion for communicative purposes. Variation in pheromone usage in this genus still presents a conundrum, highlighting the need for additional studies to understand the selective forces shaping the evolution of pheromone composition.
期刊介绍:
It is the aim of Chemoecology to promote and stimulate basic science in the field of chemical ecology by publishing research papers that integrate evolution and/or ecology and chemistry in an attempt to increase our understanding of the biological significance of natural products. Its scopes cover the evolutionary biology, mechanisms and chemistry of biotic interactions and the evolution and synthesis of the underlying natural products. Manuscripts on the evolution and ecology of trophic relationships, intra- and interspecific communication, competition, and other kinds of chemical communication in all types of organismic interactions will be considered suitable for publication. Ecological studies of trophic interactions will be considered also if they are based on the information of the transmission of natural products (e.g. fatty acids) through the food-chain. Chemoecology further publishes papers that relate to the evolution and ecology of interactions mediated by non-volatile compounds (e.g. adhesive secretions). Mechanistic approaches may include the identification, biosynthesis and metabolism of substances that carry information and the elucidation of receptor- and transduction systems using physiological, biochemical and molecular techniques. Papers describing the structure and functional morphology of organs involved in chemical communication will also be considered.