Feeding of two species of Scydmaeninae "hole scrapers", Cephennium majus and C. ruthenum (Coleoptera: Staphylinidae), on oribatid mites

Jałoszyński, Paweł; Olszanowski, Ziemowit

doi:10.14411/eje.2016.048

Cited by 12 publications

(6 citation statements)

References 13 publications

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“…Under normal conditions, Euphthiracaroidea are well protected by chemistry, whereas Phthiracaroidea lack chemical defense but can withstand significantly higher forces to protect them from potential predators. The evolutionary arms race, however, did not stop at this point and so they too can fall prey to very specialized predators like some species of staphylinid beetles which are roughly in the same size range as their prey (for example so called ‘hole scrapers’; [25–28, 55]).…”

Section: Discussionmentioning

confidence: 99%

Under pressure: force resistance measurements in box mites (Actinotrichida, Oribatida)

Schmelzle

Blüthgen

2019

Front Zool

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Background Mechanical defenses are very common and diverse in prey species, for example in oribatid mites. Here, the probably most complex form of morphological defense is known as ptychoidy, that enables the animals to completely retract the appendages into a secondary cavity and encapsulate themselves. The two groups of ptychoid mites constituting the Ptyctima, i.e. Euphthiracaroidea and Phthiracaroidea, have a hardened cuticle and are well protected against similar sized predators. Euphthiracaroidea additionally feature predator-repelling secretions. Since both taxa evolved within the glandulate group of Oribatida, the question remains why Phthiracaroidea lost this additional protection. In earlier predation bioassays, chemically disarmed specimens of Euphthiracaroidea were cracked by the staphylinid beetle Othius punctulatus , whereas equally sized specimens of Phthiracaroidea survived. We thus hypothesized that Phthiracaroidea can withstand significantly more force than Euphthiracaroidea and that the specific body form in each group is key in understanding the loss of chemical defense in Phthiracaroidea. To measure force resistance, we adapted the principle of machines applying compressive forces for very small animals and tested the two ptyctimous taxa as well as the soft-bodied mite Archegozetes longisetosus . Results Some Phthiracaroidea individuals sustained about 560,000 times their body weight. Their mean resistance was about three times higher, and their mean breaking point in relation to body weight nearly two times higher than Euphthiracaroidea individuals. The breaking point increased with body weight and differed significantly between the two taxa. Across taxa, the absolute force resistance increased sublinearly (with a 0.781 power term) with the animal’s body weight. Force resistance of A. longisetosus was inferior in all tests (about half that of Euphthiracaroidea after accounting for body weight). As an important determinant of mechanical resistance in ptychoid mites, the individuals’ cuticle thickness increased sublinearly with body diameter and body mass as well and did not differ significantly between the taxa. Conclusion We showed the feasibility of the force resistance measurement method, and our results were consistent with the hypothesis that Phthiracaroidea compensated its lack of chemical secretions by a heavier mechanical resistance based on a different body form and associated build-up of hemolymph pressure (defensive trade-off). Electronic supplementary material The online version of this article (10.1186/s12983-019-0325-x) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Under pressure: force resistance measurements in box mites (Actinotrichida, Oribatida)

Schmelzle

Blüthgen

2019

Front Zool

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“…The mandibular part is formed by a ridge in Sphaerius and by a process in hydraenids and ptiliids, with a matching labral concavity present in both cases. In the scydmaenine species, a mandibular process forms a concavity which fits with the lateral labral edge (Jałoszyński & Olszanowski, ). The grinding mola of Sphaerius is enclosed in the preoral cavity and firmly connected with the main body of the mandible, as is the case in most other groups of beetles where it is present.…”

Section: Discussionmentioning

confidence: 99%

Cephalic anatomy of Sphaeriusidae and a morphology‐based phylogeny of the suborder Myxophaga (Coleoptera)

Yavorskaya

Anton

Jałoszyński

et al. 2018

Systematic Entomology

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Myxophaga are a small group of beetles, but phylogenetically crucial as one of the four coleopteran suborders. The monogeneric Sphaeriusidae, one of four myxophagan families, comprise about 20 species, most of them living in moist substrate at river edges. The morphology of the minute hemispherical adult is very insufficiently known. Consequently, we document external and internal head structures using scanning electron microscopy, microtome sections and three-dimensional reconstructions. The results are discussed with respect to effects of miniaturization and also functional aspects, especially microphagous feeding habits. The head of Sphaerius is less affected by size reduction compared with other beetles of the same size class (e.g. larger Ptiliidae, Corylophidae). Features related to very small size are the absence of externally visible ridges and a partial shift of the brain into the prothorax. The cephalic musculature is apparently not affected. The feeding apparatus is similar to what is found in microphagous species of Polyphaga, especially in Scirtoidea and Staphyliniformia. However, in contrast to polyphagans with similar feeding habits, the hypopharyngeal longitudinal ridge (or process) of Sphaerius is strongly reduced and a fimbriate galea is lacking. The observed features are also evaluated in a cladistic analysis of larval and adult characters. The results are distinctly in conflict with branching patterns suggested by analyses of molecular data, but in agreement with previous morphological studies. In contrast to a pattern obtained in a recent molecular study -(Hydroscaphidae + (Torridincolidae + (Sphaeriusidae + Lepiceridae))) -our analyses yielded Lepiceridae as sister to the remaining Myxophaga (branch support 9), and Sphaerius as sister taxon of Hydroscaphidae (branch support 5). The monophyletic origin of the latter two taxa is supported by unusual synapomorphies of adults and larvae. Sphaerius is characterized by numerous autapomorphies of the head: a labro-mandibular locking device, a bipartite M. frontoepipharyngalis (M9) with subcomponents oriented in the opposite direction, a deep antennal furrow, an intercalary antennomere with a structure resembling a sucking disc, a strongly elongated flagellomere 1, a compact three-segmented antennal club, strong bundles of M. tentorioscapalis (M4) originating on the posterior head capsule, a concave anterior side of maxillary palpomere 2, and an elongated second pair of tormae posteriorly connected with a process of the hypopharyngeal suspensorium.

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“…There are, however, specialists among scydmaenines that have evolved bizarre and unique morphological structures with the sole function of capturing and immobilizing heavily sclerotized oribatids and uropodines, adaptations that make it impossible to feed on any other type of prey (Jałoszyński and Beutel, 2012;Jałoszyński and Olszanowski, 2016). The crucial component of such a narrowly specialized feeding apparatus is a pair of suckers located on the labium (i.e., the lower lip).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…And although a suggestion that scydmaenines may feed on armoured mites was published over a century ago (Reitter, 1909), the functional mouthpart morphology and details of the surprisingly complex feeding process were elucidated only recently (Jałoszyński and Beutel, 2012;Jałoszyński and Olszanowski, 2016).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Cephenniini use the suckers to immobilize their prey, which adheres to the predator's labium throughout the entire feeding process. One short mandible grinds a tiny hole in the mite's cuticle, the connection between the beetle's mouth opening and its prey is tightly sealed by specialized membranous structures, digestive juices are injected, and eventually liquefied tissues are ingested (Jałoszyński and Olszanowski, 2016). Stenichnus, in contrast, uses its labial suckers only in the initial phase of attack, to catch and lift a mite; then slender falciform mandibles take over the leading role in breaching the prey's defences and the mite is killed by the beetle inserting one mandible into its mouth opening.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Ninety million years of chasing mites by ant-like stone beetles

2017

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Among insects, the largest group of the Animal Kingdom, rove beetles (Staphylinidae) have undergone an enormous adaptive radiation that resulted in over 62,000 extant species (A.F. Newton, unpublished database) showing diverse body forms, structures and feeding specializations combining predaceous, mycophagous, saprophagous and ACCEPTED MANUSCRIPTA C C E P T E D M A N U S C R I P T 2 phytophagous habits in one family. The morphology of extinct and extant species is well studied, but the evolutionary history of such a broad range of adaptations is scarcely documented in the fossil record, and therefore poorly understood. One of the most puzzling specializations is that of predaceous ant-like stone beetles (Scydmaeninae), a staphylinid subfamily whose members choose not a soft-bodied prey, but the most heavily sclerotized, well-protected armoured mites. Scydmaenines have evolved a unique prey capturing apparatus with adhesive suckers to capture their prey, and the feeding process is remarkably long, often exceeding 30 h. The mouthparts with paired suckers cannot be used to catch any other kind of prey, and therefore finding such a device in extinct taxa implies specialized acarophagy. For the first time, we demonstrate that this very narrow specialization has ancient origins, and the Mesozoic (Turonian)Hyperstenichnus vendeanus Jałoszyński & Perrichot, gen. et sp. nov. from Vendean (French) amber was already an advanced, specialized mite killer. Surprisingly, the mouthpart modifications of the new species are more advanced than those in its extant relatives, suggesting that its (possibly too) narrowly specialized lineage has gone extinct.A long stasis of morphological structures is well known among Staphylinidae, and now also antiquity of narrow feeding specializations in rove beetles can be postulated, with unique habits remaining unchanged for over 90 million years.

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Feeding of two species of Scydmaeninae "hole scrapers", Cephennium majus and C. ruthenum (Coleoptera: Staphylinidae), on oribatid mites

Cited by 12 publications

References 13 publications

Under pressure: force resistance measurements in box mites (Actinotrichida, Oribatida)

Under pressure: force resistance measurements in box mites (Actinotrichida, Oribatida)

Cephalic anatomy of Sphaeriusidae and a morphology‐based phylogeny of the suborder Myxophaga (Coleoptera)

Ninety million years of chasing mites by ant-like stone beetles

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