Species-specific aggregation pheromones contribute to coexistence in two closely related thrips species

Abstract

Pheromones play an important role in mediating interspecific interactions in insects. In an insect community, pheromones can reveal information about the senders, which could be used by other members of the food web (competitor, natural enemies, etc.) to their own advantage. The aggregation pheromones of two closely related thrips species, Frankliniella occidentalis and Frankliniella intonsa, have been identified with the same major compounds, (R)-lavandulyl acetate and neryl (S)-2-methylbutanoate, but in different ratios. However, the roles of the aggregation pheromones in the interspecific interactions between these two closely related species are unknown. Here, we investigated the roles of major aggregation pheromone compounds in interspecific interactions between F. occidentalis and F. intonsa for both long and short ranges. The results showed that, at tested doses, neither aggregation pheromone-induced long range cross-attraction nor short range cross-mating was detected between F. occidentalis and F. intonsa. Field-trapping trials showed that the species-specificity in aggregation pheromones was regulated by the ratio of two major compounds. However, species-specific blends of the two major compounds had no effect on short-range interactions between these two species. Our data from the thrips species provide support for the 'aggregation model of coexistence', explaining the species-specific pheromone-mediated coexistence of closely related species. Thus, species-specific pheromones could be one of the factors affecting population dynamics and community structure in closely related insects with similar niches.

Trap colour and aggregation pheromone dose affect the catch of western flower thrips in blackberry crops

“…The function of ( R )‐lavandulyl acetate may be related to mediating interspecific interactions of F. occidentalis and other related thrips. In fact, it has recently been reported that this compound mediates the aggregation of F. occidentalis and Frankliniella intosa (Geng, Li, Zhang, Zhang, & Lu, 2017; Li et al., 2019). However, when both species do not coexist, it seems that ( R )‐lavandulyl acetate is not necessary to attract F. occidentalis (Kirk, 2017).…”

Characterization of Male-Produced Aggregation Pheromone of the Bean Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidae)

“…Characteristic species-specific ratios of major to minor compounds have been recorded in F. occidentalis and F. intonsa (Zhang et al 2011 ; Zhu et al 2012 ), although these ratios can change during the day (Li et al 2017 ). Field trials in China have recently shown a differential catch between the two species with two different compound ratios (Li et al 2018 ), suggesting the two compounds are components of one pheromone. However, field trials in Spain with F. occidentalis , using a range of release rates and ratios, did not find a ratio that caught more than the major compound alone (Dublon 2009 ; Sampson 2014 ).…”

Spinetoram resistance drives interspecific competition between Megalurothrips usitatus and Frankliniella intonsa

“…Among the indistinguishable species belonging to thrips, Megalurothrips usitatu s (Bagnall) and Frankliniella intonsa (Trybom), two of the most common flower‐dwelling thrips, currently have caused huge damage to a wide range of leguminous crops throughout the world 20,21 . As two closely related thrips, M. usitatus and F. intonsa share a number of similarities, including biological traits, occurrence pattern and behavior habits 22,23 . The two devastating thrips have posed an increasing threat to the cowpea industry in China, 23,24 leading to large economic losses through yield reductions and management costs.…”