Biology subjects

Gries, R.

Publications and source records attributed to Gries, R..

3 recordsLinked to original sources

bioRxiv2025

Glandular quinoline-derivates protect crustacean woodlice from spider predation

In evolutionary time, aquatic crustaceans colonized land and faced new terrestrial predators such as spiders and ants. Working with the crustacean woodlouse Porcellio scaber, we tested the hypothesis that the shift from aquatic to terrestrial habitat prompted the evolution of defensive metabolites against terrestrial predators. When attacked by a predator, P. scaber woodlice expel proteinaceous secretions from their tegumental glands. Analyses of gland secretion extracts by gas chromatography-mass spectrometry and by liquid-chromatography-tandem mass spectrometry revealed four metabolites: methyl 8-hydroxy-quinoline-2-carboxylate, methyl 8-hydroxy-4-methoxy-quinoline-2-carboxylate, methyl 8-(sulfooxy)quinoline-2-carboxylate, and methyl 4-methoxy-8-(sulfooxy)quinoline-2-carboxylate, the latter three being natural products not previously known. In behavioural experiments, Steatoda grossa spiders preyed on chemically undefended Tenebrio molitor beetles but avoided chemically defended P. scaber. When beetles were rendered chemically defended by topical applications of either P. scaber gland secretion extract or synthetic metabolites identified in these extracts, spiders rejected the beetles as prey. Our data support the hypothesis that the evolutionary transition of crustaceans from aquatic to terrestrial habitats prompted the evolution of defensive metabolites against terrestrial predators. We show that crustaceans, like many insects, are chemically defended against predators. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=47 SRC="FIGDIR/small/645209v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1efd0forg.highwire.dtl.DTLVardef@7804acorg.highwire.dtl.DTLVardef@17ad216org.highwire.dtl.DTLVardef@76d666_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstractUnder attack by the predatory spider Steatoda grossa, the crustacean Porcellio scaber releases four defensive metabolites: methyl 8-hydroxy-quinoline-2-carboxylate, methyl 8-hydroxy-4-methoxy-quinoline-2-carboxylate, methyl 8-(sulfooxy)quinoline-2-carboxylate, and methyl 4-methoxy-8-(sulfooxy)quinoline-2-carboxylate, the latter three previously unknown natural products.

ecology↗

bioRxiv2020

Cheese or cheese infusions - Ecological traps for mosquitoes and spotted wing Drosophila

We tested the hypothesis that the "ecological trap" phenomenon (a mismatch between a habitats perceived attractiveness and its actual quality, resulting in a population sink) is exploitable for pest control. We selected mosquitoes as modal organisms, because selection of an oviposition site by adult female mosquitoes in response to its perceived attractiveness is of paramount importance for the development and survival of their larval offspring. In laboratory and/or field experiments, we show that (i) each of five cheese varieties tested (Raclette, Pecorino, Brie, Gruyere, Limburger) strongly attracts females of both the yellow fever mosquito, Aedes aegypti, and the common house mosquito, Cx. pipiens; (ii) cheese infusions, or headspace odorant extracts (HOEs) of cheese infusions, significantly affect oviposition choices by Cx. pipiens and Ae. aegypti, (iii) HOEs contain at least 13 odorants; (iv) in field settings, cheese infusions more effectively stimulate oviposition by Cx. pipiens and Culiseta incidens than bluegrass (Poa sp.) infusions, and also capture (by drowning) the spotted wing Drosophila (SWD); (v) the microbe composition of home-made cheese infusions modulates oviposition choices by mosquitoes; and (vi) the type of cheese infusion coupled with its nutritional content strongly affects the survivorship of mosquito larvae. In combination, our data show that microbial metabolites associated with cheese and cheese infusions are both attractive to adult mosquitoes seeking hosts and oviposition sites, respectively, and are toxic to mosquito larvae. These microbes and their metabolites could thus be coopted for both the attract and the kill function of "attract & kill" mosquito control tactics. Implementation of customizable and non-conventional nutritional media, such as home-made cheese infusions, as microbe-based ecological traps presents a promising concept which exploits insect ecology for insect control.

ecology↗

bioRxiv2020

Nectar-dwelling microbes of common tansy are attractive to its mosquito pollinator, Culex pipiens L.

BackgroundThere is widespread interkingdom signalling between insects and microbes. For example, microbes found in floral nectar may modify its nutritional composition and produce odorants that alter the floral odor bouquet which may attract insect pollinators. Mosquitoes consume nectar and can pollinate flowers. We identified microbes isolated from nectar of common tansy, Tanacetum vulgare, elucidated the microbial odorants, and tested their ability to attract the common house mosquito, Culex pipiens. ResultsWe collected 18 microbial isolates from T. vulgare nectar, representing at least 12 different taxa which we identified with 16S or 26S rDNA sequencing as well as by biochemical and physiological tests. Three microorganisms (Lachancea thermotolerans, Micrococcus lactis, Micrococcus luteus) were grown on culture medium and tested in bioassays. Only the yeast L. thermotolerans grown on nectar, malt extract agar, or in synthetic nectar broth significantly attracted C. pipiens females. The odorant profile produced by L. thermotolerans varied with the nutritional composition of the culture medium. Surprisingly, all three microbes grown separately, but presented concurrently, attracted fewer C. pipiens females than L. thermotolerans by itself. ConclusionsFloral nectar of T. vulgare contains various microbes whose odorants contribute to the odor profile of inflorescences. In addition, L. thermotolerans produced odorants that attract Cx. pipiens females. As the odor profile of L. thermotolerans varied with the composition of the culture medium, we hypothesize that microbe odorants inform nectar-foraging mosquitoes about the availability of certain macro-nutrients which, in turn, affect foraging decisions by mosquitoes.

ecology↗