Cuticular Extracts from Acromis sparsa (Coleoptera: Cassidinae) Mediate Arrestment Behavior of the Commensal Canestriniid Mite Grandiella rugosita

Abstract

Astigmatid mites in the family Canestriniidae are often closely associated with tortoise leaf beetles (Chrysomelidae: Cassidinae). For example, the survival of the commensal canestriniid mite Grandiella rugosita depends on dispersal to the cassidine beetle Acromis sparsa. Here, we tested whether the beetle cuticle provides chemical cues for host recognition for G. rugosita. In two-choice assays with cuticular extracts from A. sparsa and the co-occurring, non-host cassidine Chelymorpha alternans offered simultaneously, mites clearly preferred the area treated with extract from their host. In no-choice assays, G. rugosita spent three times longer and moved three times slower on host cuticular extracts compared to non-host extracts and the solvent control. Analyses of the chemical composition of cuticular extracts from males and females of A. sparsa and C. alternans revealed complex mixtures of mainly methyl branched hydrocarbons, which clearly separated both species in a principal component analysis. We found no qualitative difference between males and females of either species, but in C. alternans quantitative differences between males and females were detected. Our results demonstrate that G. rugosita is able to discriminate between cuticular extracts from its host A. sparsa and the non-host C. alternans. The components eliciting the observed arrestment behavior remain to be determined.

Variation in contact chemical cues may mediate differential predator response in the colour polymorphic tortoise beetle,Chelymorpha alternans

“…To assess whether phenotypes differ in their CHC profiles, elytral CHCs were extracted from three phenotypes using a hexane extraction protocol modified from Beran et al (2014). All beetles were taken from a large breeding population of C. alternans maintained at STRI facilities in Gamboa, Panama.…”

Kin recognition in a subsocial treehopper (Hemiptera: Membracidae)

“…The presence or absence of a compound in the chromatogram was determined following Flores-Prado et al (2008) and Aguilera-Olivares et al (2016), by identifying compounds based on comparisons of their retention index and mass spectrum with those in the NIST14 database, with authentic standards (when available) and, eventually, with data from the literature (Flores-Prado et al, 2008;Cocchiararo-Bastias et al, 2011;Calderón-Fernández & Juárez, 2013;Beran et al, 2014;El-Sayed, 2014;Aguilera-Olivares et al, 2016). Then, 4 l of the re-dissolved extracts were injected in a Shimadzu model GCMS-QP 2010 Ultra gas chromatograph (Shimadzu, Kyoto, Japan) equipped with an Rtx-5MS Crossbond 5% diphenyl 95% dimethyl polysiloxane (Restek, Bellefonte, Philadelphia) capillary gas chromatograph (GC) column (length 30 m, internal diameter 0.25 mm, film thickness 0.25 m) and used in the splitless mode.…”

“…Retention indexes were calculated on the basis of chromatograms obtained from the periodic injection of a standard alkane mixture. The presence or absence of a compound in the chromatogram was determined following Flores-Prado et al (2008) and Aguilera-Olivares et al (2016), by identifying compounds based on comparisons of their retention index and mass spectrum with those in the NIST14 database, with authentic standards (when available) and, eventually, with data from the literature (Flores-Prado et al, 2008;Cocchiararo-Bastias et al, 2011;Calderón-Fernández & Juárez, 2013;Beran et al, 2014;El-Sayed, 2014;Aguilera-Olivares et al, 2016). An identification was proposed if the retention index did not differ by more than five units and the similarity index of the mass spectrum was over 85% compared with the database or the literature.…”

Cuticle hydrocarbons in saline aquatic beetles

“…On the other hand, CHCs show a significant degree of plasticity conferring a notable intraspecific variability (Howard & Blomquist, 1982; Gibbs & Rajpurohit, 2010). Many studies have reported differences in CHC profiles within species depending on sex (e.g., Beran et al, 2014; Pattanayak et al, 2014), developmental stage (e.g., Bagnères et al, 1996), the feeding state of individuals (e.g., Jacob & Hansen, 1986; Alabi et al, 2011), environmental conditions (Toolson, 1982) or rearing temperature (e.g., Rouault et al, 2004; Rajpurohit et al, 2017). …”