Undescribed anatomical features of the gut of the house cricket,Acheta domesticus L. (Insecta,Orthoptera)

Summary

The following new anatomical features of the gut of Acheta domesticus are described and discussed:

• 1.A thin-walled dorsal evagination of the oesophagus, which may serve to circulate digestive fluid in the crop.

• 2.Lateral invaginations of the wall of the posterior oesophagus and anterior crop, separated from the circular muscle layer and allowing considerable enlargement of the foregut during feeding.

• 3.Strands of muscle and connective tissue linking the caeca and crop to the thoracic cuticle, innervated in part from the prothoracic ganglion, which may serve to register the extent of gut filling.

• 4.Evidence from the arrangement of the gut tracheae and nerves of rotation of parts of the gut from their original ancestral position, the gizzard and caeca being rotated through 90° and the crop through 180°. It is suggested that these rotations have been necessary to accommodate the gut components to changes in the shape and proportions of the body during the evolution of the cricket lineage.

     

Foregut structures of freshly moulted exuviae from Maja crispata,Cancer pagurus and Pseudosesarma moeschi (Decapoda: Brachyura)

Periodic moulting is vital for the growth of crustaceans. The process is characterized by a complete replacement of the mineralized exoskeleton, including eyestalks, legs, the pleon as well as the foregut and hindgut. In the present study a series of freshly moulted brachyuran exuviae [Maja crispata Risso, 1827; Cancer pagurus Linnaeus, 1758 and Pseudosesarma moeschi (De Man, 1888)] were investigated concerning the remaining calcified foregut structures. All investigated exuviae show part or complete degradation of the lateral expanded ossicles of the gastric mill (e.g. ossicles II, V and IX). Most of the ossicles of the pyloric filter are unaffected by the degradation processes. Reduction of the calcium content and the increasing flexibility of the foregut ossicles enable the passage of the bigger “old” foregut through the smaller oesophagus of the newly formed foregut. The gastric teeth of the examined exuviae are not influenced by the moulting process.     

Fungal spore-feeding by adult and larval Mecynothrips hardyi (Priesner) (Thysanoptera: Phlaeothripidae: Idolothripinae)

Mecynothrips hardyi (Priesner), a member of the phlaeothripid subfamily Idolothripinae, is demonstrated to feed on whole fungal spores on hanging dead leaves and branches of Acacia harpophylla (brigalow). The diet primarily comprises spores of a recently described species of Dothiorella (Botryosphaeriaceae). The 14μm-wide food canal enclosed by the maxillary stylets is evidently adapted to imbibe whole spores, and the foregut includes a sclerotized proventriculus with internal ridges that presumably aids in the abrasion and thus digestion of the thick-walled spores.     

Comparative morphology of the foregut of four Gnathophausia species (Crustacea; Mysidacea; Lophogastrida). Relationships with other taxa

The features of the foregut of Gnathophausia ingens Dohrn, 1870, G. zoea W.-Suhm, 1875, G. longispina G. O. Sars, 1883 and G. gracilis W.-Suhm, 1875 (Crustacea, Mysidacea, Lophogastrida, Lophogastridae) are described, based on scanning electron microscopy. Comparisons are made with the foregut of related taxa, particularly with Eucopia, the only genus constituting the second family (Eucopiidae) of the Lophogastrida. The foreguts of Gnathophausia and Eucopia exhibit (1) common features, which might be characteristic of the sub-order Lophogastrida, (2) more similarities with those of the Decapoda than those of the sub-order Mysida. But preliminary observations suggest that the stomach is obviously smaller than that of the similarly sized Decapoda. The foregut of Gnathophausia is morphologically unique to this genus, although each species exhibits small specific differences.     

The food of Riccardoella limacum (Schrank) — Acari-Trombidiformes and its relationship with pulmonate molluscs

Summary

Knowledge of the anatomy and contents of the alimentary canal of R. limacum was obtained by using transverse and longitudinal sections of adult mites. Histological and histochemical techniques revealed the absence of slug mucus and the presence of slug amoebocytes in the gut caeca of the mite. The evidence available supports the contention that the slug mite is a blood feeder and obtains this food by producing a feeding tube or ‘stylostome’ in the tissues of its host.     

Natural diet of the freshwater anomuran Aegla longirostri (Crustacea,Anomura, Aeglidae)

The present study characterized the diet of Aegla longirostri from southern Brazil, in relation to seasonality, size and sex of the animals. The aeglids were sampled bimonthly, from October 1999 to August 2000. The animals were dissected and the Stomach Repletion Degree (RD) and the food items contained in each stomach were recorded. For each food item with RD?0.5, the Relative Importance Index (RII) was calculated. Of 399 animals collected, 305 had RD?0.5. The following items were found in the stomachs: plant tissue, non‐identified material, sediment, and fragments of adult insects, as well as fragments of Aegla sp., mollusc shells, fish scales and dipteran larvae. Independently of size class and sex, the animals showed a preference for plant tissue. These results demonstrate that A. longirostri has an omnivorous feeding habit, and is mainly herbivorous.     

A new heteromorphic deutonymph (Hypopus) of a sarcoptiform mite parasitic under the skin of a toucan

Summary

A study of the form and functioning of Philine angasi and Philine auriformis. Philine angasi feeds on the bivalve Chione stutchburyi by extrusion of the buccal bulb. The radula is degenerate and plays no part in the ingestion of food. Philine auriformis ingests Nucula hartvigiana, the buccal bulb acting as a suction pump. The buccal bulb is not eversible and the buccal mass carries the prey from the buccal cavity to the oesophagus. The feeding and form of these species are compared with that of Philine aperta. It is shown that the musculature of the buccal region is modified to suit the different feeding methods.     

Aggressive,omnivorous, invasive: the Erythraean moon crab Matuta victor (Fabricius, 1781) (Crustacea: Decapoda: Matutidae) in the eastern Mediterranean sea

Since its first sighting in 2012 in Haifa Bay, Israel, the population of the Indo-Pacific moon crab, Matuta victor, has increased greatly along the Israeli littoral and spread to Lebanon and the Mediterranean coast of Turkey. To examine possible interactions with the Levantine nearshore psammophilic community, the crab’s feeding behaviour was observed in situ and the foregut contents of 69 specimens collected in December 2015 and June 2016 were analysed. Its omnivorous diet was confirmed and previously unknown intraspecific competitive feeding behaviour is reported. The agonistic behaviour may denote behavioural flexibility that enables the crabs to colonize and persist in a depauperate novel habitat. Site-specific disturbance regimen related to human activities seems to have had a critical role in driving the rapid population increase.     

Diet and feeding behaviour of the leaf-litter frog Ischnocnema henselii (Anura: Brachycephalidae) in Araucaria rain forests on the Serra Geral of Rio Grande do Sul,Brazil†

Abstract

We analysed the diet of Ischnocnema henselii from a subtropical Araucaria forest through stomach flushing. The identified prey items comprised arthropods such as spiders, ants, orthopterans, collembolans and homopterans. We consider I. henselii to be a nocturnal and opportunistic sit-and-wait predator. Small animals are preferred. Because this species lives permanently on the forest floor, we also determined the composition of the habitat's leaf-litter mesofauna. By using Winkler sieve extraction, we obtained a spectrum of small invertebrates that reflected the prey in the stomach contents well. The only exceptions were mites, the most abundant leaf-litter inhabitants, which frogs either avoided or ignored. Our results represent the first information on the diet of I. henselii and are discussed in comparison with data on related species and in relation to the relevance of this predator within the food web of subtropical montane rain forests in southern Brazil.     

Four new earthworms of the genus Amynthas (Oligochaeta: Megascolecidae) from Mount Emei,Sichuan Province,China

Four new species were collected from Mt. Emei, Sichuan Province, China. They are Amynthas leshanensis sp. nov., Amynthas gilvus sp. nov., Amynthas retortus sp. nov. and Amynthas orbicularis sp. nov. The first three species could be assigned to the Amynthas sieboldi group and the last species could be assigned to the Amynthas aeruginosus group according to the definition of Sims and Easton. A. leshanensis sp. nov. has the male pore porophore surrounded by a large irregular-shaped pad which extends from 17/18–½ XIX, and the intestinal caeca are complex. A. gilvus sp. nov. has each male pore on a slightly raised elliptical glandular flat-top pad, with a pointed extension lateral to each porophore. Amynthas retortus sp. nov. has a pair of small, round post-setal genital papillae medial to male porophores on XVII, spermathecal seminal chambers are twisted into zigzags and accessory glands are present on spermathecae and prostate gland areas. A. orbicularis sp. nov. has the spermathecal pores near dorso-lateral, complex intestinal caeca complex, three accessory glands with long ducts near the male pores, and the spermathecal seminal chambers are twisted into zigzags. The barcode data (partial sequence of mitochondrial cytochrome c oxidase subunit I) of each species has been submitted to the National Center of Biotechnology Information GenBank.

http://zoobank.org/urn:lsid:zoobank.org:pub:5B82315E-5CF8-4048-87C4-B702021464B5     

A new earthworm genus Nouraguesia gen. nov. from French Guiana with description of two new species (Oligochaeta,Glossoscolecidae)

Nouraguesia gen. nov., consisting of three species, is described from Eastern Amazonia. Species belonging to this genus are middle-sized earthworms inhabiting, based on our experience, decomposing tree logs and space filled with detritus between leaf-axils and trunk (e.g. in some palm species). The new genus is morphologically similar to the genus Andiorrhinus, but differs from it by the presence of numerous caeca encircling the intestine in segment 27. The three species belonging to the newly established genus are known from state Amapa in Brazil (N. amaparis (Righi, 1971)); and French Guiana (N. parare sp. nov., N. souadae sp. nov.).     

Larval food sources of Centris (Heterocentris) analis (Fabricius, 1804) (Hymenoptera: Apidae), an oil-collecting bee

Pollen analysis of larval food allows identification of plants used as nest provision sources. Considering the importance of Centris analis in pollination, we aimed to identify its plant sources, food niche width in Cerrado, and analyze the use of sources between cool/dry and warm/wet seasons. We sampled 22 nests collected in two areas from February 2008 to October 2009. Heteropterys spp. (Malpighiaceae) were the main pollen sources, but Byrsomia spp. (Malpighiaceae), Banisteriopsis malifolia (Malpighiaceae), Solanum lycocarpum (Solanaceae) and Machaerium spp. (Leguminosae) were also important food sources. There was no difference in the use of the sources between the seasons (F_1,100?=?0.001; p?=?0.979). Despite the high number of pollen types (n?=?14) the food niche widths were low, H?=?0.777 and H?=?0.949, which can be explained by the dominance of some food items. Hence, C. analis use, profusely, a few plants as food sources that could be considered conservation targets.     

A study on the developmental bionomics of Dineutes indicus Aube (Gyrinidae,Coleoptera)

Australothis volatilis sp. n., the only species of Heliothinae endemic to New Zealand, is described. The larval food plants, Vittadinia spp., are recorded and other biological information is provided. The male and female genitalia, penultimate and final instar larva, pupa, adult, native food plant, and habitat are illustrated.     

Foraging ecology of the giant Amazonian ant Dinoponera gigantea (Hymenoptera,Formicidae, Ponerinae): activity schedule,diet and spatial foraging patterns

This study provides a detailed account of the natural history and foraging biology of the ponerine ant Dinoponera gigantea in a rainforest in north Brazil. The species nests on the ground and the colonies contain 70–96 workers. Ant activity is negatively correlated with temperature, and is more intense at dawn and dusk. Foragers leave the nest independently and search for food individually on the leaf litter, within ca 10 m around the nest. Workers are opportunistic feeders that collect seeds and fruits, and hunt for live prey as well as scavenge for dead animal matter. The dry weight of food items ranges from <10 mg (spiders, insect parts) to >400 mg (seeds, fruits). There is no nestmate recruitment during the search for or retrieval of food, irrespective of food type and size. Foragers have a high directional fidelity, and ants from neighbouring colonies may engage in ritualized territorial contests at the border of their foraging areas. The foraging ecology of D. gigantea is compared with other ponerine species living in tropical forests, as well as with other ant groups showing similar behavioural patterns.     

Foregut anatomy and predation by Charonia lampas (Gastropoda: Prosobranchia: Neotaenioglossa) attacking Ophidiaster ophidianus (Asteroidea: Ophidiasteridae) in the Açores,with a review of triton feeding behaviour

This paper is the first to describe, in detail, the process of feeding by a species of Charonia. As Charonia lampas commenced attacking its sea star prey, Ophidiaster ophidianus, the latter autotomized its trailing arm and escaped. The pursuing C. lampas ate this arm. The results of this study are not in accord with the established view of feeding by species of Charonia. Firstly, C. lampas did not inject either a venom into its prey to paralyse it nor an acid to access it and, second, nor did it pierce the skeleton of its prey and suck out the tissues, all as reported in the literature. Rather, in the case herein described, C. lampas held and manipulated its prey with the foot and used its taenioglossan radula located at the end of the extendible pleurembolic proboscis to scrape and ingest the soft tissues of the sea star and, subsequently, consume the remaining skeletal components again using the proboscis and contained radula. These two phases of consumption were followed by two matching phases of faeces production. Also described is the foregut anatomy of C. lampas, including, for the first time, the minute jaws and the histology of the salivary glands, and for which comparison is made with those of the known acid-producing structures of representatives of the Cassidae and other Ranellidae. As finally described, predator and prey clearly recognised each other signifying an identifiably intimate relationship. Charonia lampas consumed only the autotomised arm and it is argued that in such a case, as an anti-predation device, autotomy is of survival benefit to both predator and prey.     

Structure and functioning of the gut in the Bullomorpha (Opisthobranchia)

Summary

A study of the form and functioning of Aglaja cylindrica and Aglaja aureopunctata. In this family the radula and gizzard plates are absent. In Aglaja cylindrica the buccal bulb has enlarged to form a pump used to suck in polychaete and nemertine worms. In Aglaja aureopunctata the buccal bulb can partially evert, enabling the species to ingest shelled opisthobranchs. In both species an oesophageal crop fulfils the role of the reduced stomach. A short review of the histology of the digestive gland is also included.     

The influence of environment and competition on the distribution of Bdellocephala punctata (Turbellaria,Tricladida) in Britain

Summary

Bdellocephala punctata (Pallas), the largest British freshwater triclad, has been recorded from thirty-four, widely distributed sites in the British Isles. This distribution does not appear to be associated with any chemical or physical characteristics of the habitats. Although B. punctata has a simple pattern of population dynamics, which normally enables it to avoid competition for food with other triclads, it is suggested that this strategy is sensitive to environmental fluctuations. A decrease in relative food supply, particularly if this is due to increased breeding overlap with a confamilial, would lead to drastic reductions or extinctions of local populations and produce the observed disjunct distribution. The possibility that it may be a comparatively recent immigrant to Britain cannot be excluded.