The secretion of the ventral glands in Cladius, Priophorus and Trichiocampus sawfly larvae

Journal of Insect Physiology

2007

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Larvae of the sawfly Arge (Hymenoptera, Argidae) are exposed to predators such as ants. Their defence mechanisms, which have been almost unstudied, were investigated by behavioural observations coupled to a morphological approach and by testing the bioactivity of several body parts. Arge larvae raised their abdomen when contacted by Myrmica rubra workers. The ants rarely bit a larva and generally retreated immediately, sometimes without contacting it. Most of those few ants that bit a larva then showed an uncoordinated walk. Crude hemolymph from a common species, A. pagana, was a feeding deterrent towards ants. Hemolymph extracts remained active up to a concentration of 0.8 µg DW extract per microlitre solution, and were more active than integument and gut extracts. We also observed ants paralysed by extracts, especially from the gut. It is likely that this toxicity is due to a polypeptide, lophyrotomin, which is known to occur in A. pullata. Six or seven non-eversible ventro-abdominal glands occurred in all species studied (A. fuscipes, A. nigripes, A. ochropus, A. pagana, A. pullata, A. ustulata). These glands contain volatiles. We consider both types of chemicals to be important in defence, and we propose that the paralysing effect is a common feature among Arge species.

Section: Discussionmentioning

confidence: 99%

Anti-predator defence mechanisms in sawfly larvae of Arge (Hymenoptera, Argidae)

Petre

Detrain

Journal of Insect Physiology

2007

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“…19,20,22,23,25,55,56 The settings first tried by using a few molecules from each chemical class were then identically processed on all molecules. For molecules occurring Volatiles were detected and identified by gas chromatography-mass spectrometry of dissected ventral glands, following references for the genera Cladius, 49 Craesus, 50 Hoplocampa, 3 and Nematus. 51 The left part of the figure is continued on the right part.…”

Section: The Process Of Sonificationmentioning

confidence: 99%

“…In the literature about the chemical profiles of the studied nematine secretions, volatile amounts are given for Cladius and Nematus species as percentages of the total secretion, 49,51 and for Craesus and Hoplocampa species as large, medium, small, or trace amounts. 3,50 Percentages were categorized from large to trace amounts: >15%, 6%-15%, 1%-5%, and <1%, respectively.…”

Section: Sonificationmentioning

confidence: 99%

“…The odor of the defensive secretions is described as unpleasant for some species belonging to the genera Nematus, Pristiphora, and Trichiocampus. 48,49 This paper aims to assess whether audio files generated by sonification constitute an approximation of the bioactivity of complex defensive secretions. Our approach compared the behavioral effects of an identical set of chemical data in two unrelated perceptive worlds, smelling versus hearing.…”

Section: Introductionmentioning

confidence: 99%

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Chemical composition: Hearing insect defensive volatiles

Giot

2021

Patterns

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“…For instance, spine-like hairs cover the larval body of Periclista, Monophadnoides (Blennocampinae) and of Cladius, Priophorus, Trichiochampus (Nematinae), and larvae are endophytic in most Heterarthrinae, as well as in the genera Cladardis (Blennocampinae), Hoplocampa, Pontania and Euura (Nematinae) (Lorenz and Kraus 1957). These morphological and behavioral traits are strategies known to protect the larvae to some extent against arthropod predators and parasitoids (BoevØ and Pasteels 1985;Price and Pschorn-Walcher 1988;BoevØ et al 1997BoevØ et al , 2000.…”

Section: Extent Of Easy Bleeding Among Sawfliesmentioning

confidence: 99%

Why does the larval integument of some sawfly species disrupt so easily? The harmful hemolymph hypothesis

Schaffner

2003

Oecologia

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The larvae of several sawfly species belonging to the Tenthredinidae (Hymenoptera) have such a low mechanical resistance in the integument that slight mechanical damage to the integument is enough to provoke the release of hemolymph at a given spot. We quantified this phenomenon, which we call "easy bleeding", by measuring the pressure needed to pierce dissected sawfly integument. We also investigated the feeding deterrance of ethanolic extracts of the hemolymph by laboratory bioassays using Myrmica rubra ant workers. These traits, integument resistance and hemolymph deterrence, were inversely related, considering 22 tenthredinid species. A negative correlation was obtained by only taking into account the species of one tenthredinid tribe, namely the Phymatocerini (nine species studied). Our results support the "harmful hemolymph hypothesis" that we present here and that assumes a functional link between these morphological and chemical traits, jointly acting as a chemical defense strategy. We suspect hemolymph deterrence to be often due to sequestration of plant secondary metabolites. We discuss the role of easy bleeding, considering the fact that sawfly larvae are frequently the prey of invertebrate and vertebrate predators. It is suggested that invertebrates such as ants were more important than vertebrates in the evolution of easy bleeding.