Comparative larval morphology of the European bone-skippers,Thyreophora cynophila (Panzer, 1798) and Centrophlebomyia furcata (Fabricius, 1794) (Diptera: Piophilidae), with notes on their coexistence and natural history

Considered at times as extinct, the European bone-skippers Thyreophora cynophila and Centrophlebomyia furcata (Diptera: Piophilidae) have been recently rediscovered in Spain, coexisting in some areas. Nevertheless, apart from their typical association with big mammal carcasses, little is known about them and the other species of subtribe Thyreophorina. In the present paper, the larval morphology of T. cynophila is described for the first time and compared with that of C. furcata. The morphology of cephalopharyngeal skeleton, the number and arrangement of the spines of ventral creeping welts, and the morphology and presence or absence of tubercles in the two last segments of the body, are the main characters allowing for larval identification of both species. Some preliminary field and laboratory observations on the behaviour and life cycle of the two species are also provided.     

Studies on the cheilostome bryozoan fauna of the Aegean island of Chios

Summary

Collections of cheilostome Bryozoans from shallow water communities around Chios yielded 101 species. Of these, 15 are rare or little known species and eight are reported from the Mediterranean for the first time. Four new species are described.

The Bryozoan benthos of the eastern Mediterranean differs in several ways from that of the western basin. In particular, a high proportion of endemic species was noted, some of which are restricted to the eastern Mediterranean. Decreased proportions of Atlantic species may be explained either by the recent immigration of such species into the Mediterranean as a whole or by the existence of barriers to migration between the east and west basins of the sea. No firm evidence of the existence of Tethyan relics is found, but the occurrence of a number of species on the West African coast, in the Mediterranean and throughout the Indo-West-Pacific suggests very ancient distribution patterns.

Notes on relative abundance, and utilization of different substrata are included.     

XLI.—Records of some parasitic worms from British vertebrates

Summary

The percentage infection with fifteen species of larval Digenea is described in ten species of littoral prosobranchs in Cardigan Bay.

In some host species percentage infection varies with the position on the shore in relation to the height above chart datum and to exposure to wave action.

These variations are attributed, partly to the behaviour of the host species, to the effects of environmental conditions on the susceptibility to infection of the first intermediate host and on the free-living stages of the parasite and to the physiological or genetical resistance of the first intermediate host.     

Disentangling prey-handling efficiency of larval newts through multivariate prey trait analysis

Multivariate prey trait analysis is a functional approach to understand predator–prey relationships. In the present study, six prey macroinvertebrate ecological traits were used to identify several key factors in the handling efficiency of seven predatory larval newt species. The results revealed a remarkable similarity in the feeding behaviour among species, suggesting a foraging behaviour convergence among species in the prey-handling efficiency of larval newts. Nevertheless, larvae of some newt species showed clear preferences for particular categories of ecological trait; for example, Lissotriton vulgaris tended to feed on macroinvertebrate taxa with random trajectory, and Calotriton asper fed on macroinvertebrate taxa with high agility. In contrast, Mesotriton alpestris showed a clear ability to feed on prey with movable accessories (cases/tubes) and patterned concealment. This study shows how multivariate approaches can complement traditional diet analyses, and the method has wide applicability across life-stages and species.     

Potential host range of myrmecophilous Arhopala butterflies (Lepidoptera: Lycaenidae) feeding on Macaranga myrmecophytes

“Plant-ants”, i.e. those symbiotic with myrmecophyte plants, defend their hosts against herbivores. Plant-ants are expected to affect the host-plant ranges of herbivores that feed on myrmecophytes. This study aimed to experimentally determine whether anti-herbivore defences by plant-ants restrict the larval host-plant ranges of four Arhopala (Lycaenidae) butterflies that feed on Macaranga (Euphorbiaceae) trees, some of which are myrmecophytes. We fed Arhopala larvae with the leaves of five Macaranga species under ant-excluded conditions to examine their potential host-plant ranges. Under ant-excluded conditions, three Arhopala species survived to the pupal stage when fed species not used in the field as well as their normal host species. Our data suggested that the aggressive behaviours of plant-ants towards leaf-feeding insects restrict the potential host-plant ranges of some Macaranga-feeding Arhopala butterflies.     

Some observations on the chaetotaxy of the legs of larval Ixodidae (Acari: Metastigmata)

Summary

The segmental chaetotaxy of the legs of some larval ixodid ticks has been studied, employing the system of nomenclature currently used for the mesostigmatic mites. Preliminary results indicate that in common with the larval Mesostigmata, the family Ixodidae has a relatively constant larval leg chaetotaxy which allows the subfamilies and tribes to be distinguished on the basis of the chaetotaxy of the tibiae.     

Natural history and ecological niche modelling of coastal Atyphella Olliff Larvae (Lampyridae: Luciolinae) in Vanuatu

ABSTRACT

The genus Atyphella Olliff includes several coastal species with larvae that were collected on coastal rock within the intertidal zone. Recent fieldwork in Vanuatu has expanded the distribution of these insects and begun to provide insight into how they are able to survive in such a unique environment. An ecological niche model is produced using Maxent to predict additional locations of coastal Atyphella in the South Pacific. Larval instars for the two species of Atyphella in Vanuatu are estimated using protergum shield width measurements. Additionally, submersion tests were performed on larvae to determine survivability in saltwater and freshwater environments. These data provide evidence for previously unknown aspects of their natural history that strongly suggest the species are multivoltine and spend a large portion of their larval stage in the intertidal zone.     

Factors linked to temporal and spatial variation in the metazoan parasite communities of green jack Caranx caballus (Günther 1868) (Pisces: Carangidae) from the Pacific coast of Mexico

ABSTRACT

Biotic or abiotic factors responsible for temporal or spatial variation in metazoan parasite communities of the green jack Caranx caballus were studied over a nine-year period using samples collected at locations along the south-central Pacific coast of Mexico. A total of 708 fish were collected from six locations between December 2009 and October 2017. Thirty-two parasite species were identified: three Monogenea, nine Digenea, two Cestoda, five Nematoda, eight Copepoda, and three Isopoda. At the component community level, parasite species richness varied significantly from seven (Zihuatanejo 2016) to 18 (Acapulco Bay 2011). The component communities and infracommunities of C. caballus exhibited a similar pattern: low species numbers, low diversity, and dominance by a single species (mainly the monogenean Pseudomazocraes selene or the digenean Bucephalus varicus). Parasite community structure and species composition varied between locations and/or sampling years. The main factors responsible for these variations were host traits such as feeding behaviour and body size, the occurrence of a set of distinctive parasite species, and possible variations in the availability of infected prey between locations.     

A new species of Prosimulium Roubaud (Diptera:Simuliidae) from Rhodesia

Summary

A new species of Prosimulium from Rhodesia is described and placed in the damarense-group; this species-group is defined and keys are given for the identification of its three constituent species in larval, pupal and adult stages.     

Growth ‘rules’ and the larvae of decapod crustaceans

Summary

Statements that have attempted to express the relationship between the sizes of successive arthropodan instars are examined with reference to published data on larval decapod crustaceans.

The conclusions reached are (a) that ‘Brooks's Law’, which simply states that the lengths of successive instars form an exponential series, generally holds good in decapod larvae, (b) that ‘Przibram's Rule’, stating that the weight increase between instars is always by some power of 2, is not supported by the observed length changes, and (c) that Gurney's suggestion that growth factors in decapod larvae do not normally exceed about 1·5 is not applicable to the order as a whole, but may be valid for some sub-groups within it.     

Champsodontidae (Pisces: Trachinoidei) in the Eastern Mediterranean: how many species are there?

ABSTRACT

Three marine fish species of the Indo-Pacific genus Champsodon were reported as invasive species in the Eastern Mediterranean between 2009 and 2012; Champsodon nudivittis, C. vorax, and C. capensis. These are presumed to invade through the Suez Canal, but only C. nudivittis is known from the Red Sea, so the presence of C. vorax and C. capensis is surprising. To test the validity of the taxonomic identification of these two species, this study combined traditional morphology, genetic barcoding, and photography investigation. Our results demonstrate that only one species, C. nudivittis, has migrated into the Eastern Mediterranean.     

A comparative study of the larval development of Monodaeus couchi (Couch), Xantho incisus Leach and Pilumnus hirtellus (Linnaeus) (Crustacea: Brachyura: Xanthidae)

Summary

Comparative accounts are given of the larval and first crab stages of three crab species belonging to the family Xanthidae: Monodaeus couchi (Couch), Xantho incisus Leach and Pilumnus hirtellus (Linnaeus). Features are discussed that distinguish the larvae of these species from those of other N.E. Atlantic brachyrhynch crabs.     

Assessment of morphometric characters to delimit species of Apolpium Chamberlin, 1930 (Pseudoscorpiones,Olpiidae)

ABSTRACT

Pseudoscorpiones is a mesodiverse order of Arachnida, with more than 3600 described species in the world. Species delimitation is sometimes difficult due to the high variability of some characters, difficulty in finding informative and useful characters for species differentiation and the subjectivity of individual specialists. The aim of this work is to explore and to evaluate the role of morphometric characters in species delimitation within the genus Apolpium (Olpiidae). Measurements of 17 structures of 57 individuals were taken and their length/width ratios calculated. Cluster analyses, principal components analyses, discriminant function analyses and non-metric multidimensional scaling were carried out. The results showed low resolution for the number of species currently recognised in the genus. These results highlight the importance of looking for other morphological characters, and also for a more rigorous assessment of previously used characters for defining species.     

LIX.—Description of a species of Palæmon from near Sydney,probably either a new species or the adult form of Palæmon (Eupalæmon) danæ, Heller

Summary

Plagues of small mammals in Australia are nearly confined to rodents, both native and introduced. Only in the arid regions do small marsupials reach plague numbers.

Records of plagues have been found as early as 1845, but in many of them there is insufficient information to identify the species involved.

Plagues can develop under three main conditions, namely (a) when species are introduced into new environments, (b) in the artificial environment of crop plants, and (c) in the natural environment.

There are records of the introduced Rattus rattus forming plagues. On colonizing Lord Howe Island in 1918 the species built up to plague numbers in two years. On other islands the species is likely to have built up large populations also. Of various reported plagues on the Australian mainland, Rattus rattus has been identified definitely on only one occasion, in western New South Wales in 1887. There are earlier reports of the introduced rats and mice occurring in large numbers in unsettled areas, but it seems more likely that the animals were native species, wrongly identified, than introduced species which had spread into the areas concerned.

Two groups of species build up to plague numbers in the artificial environment of crop plants. These are Rattus conatus and some other native species which infest sugar-cane in Queensland, and Mus musculus which often infests wheatfields but also forms plagues in other habitats. Both groups infect the crop from a neighbouring natural habitat. Detailed ecological studies have been carried out on both these types of infestation. Reports of dispersal of plagues of Mus musculus need investigation.

Mus musculus can form plagues over a wide range of habitats, from the arid regions of central Australia to the high rainfall areas of tropical Queensland. The status of the form inhabiting the arid regions needs study.

The arid regions of Australia provide a special environment in which live a number of species of small mammals, both eutherians (rodents) and marsupials. In this habitat breeding occurs when there is a sufficient rainfall, and is not regulated at its extremes by an annual climatic cycle. Some of the riverine lands within the region receive drainage from outside, and this modifies the relationship with rainfall in the Lake Eyre Basin particularly. Under favourable conditions several species of the small mammals can build up to plague numbers. In this they appear to differ markedly from the small mammals of other deserts of the world. The special features of the Australian arid environment which allow this are unknown.

Plagues of Rattus villosissimus are generated in the tablelands to the south of the Gulf of Carpentaria, and hordes of the rodents disperse in large numbers, mostly moving out of the home territory along the course of rivers draining it to the south, and sometimes also to the north. The little information available concerning the populations suggests similarities with the cyclic changes which take place in populations of voles and lemmings in the northern hemisphere. There is no good information about the period of recurrence of the plagues, present records showing a range from three to seventeen years.

The little information available about the plagues of small mammals in Australia suggests parallels with such plagues elsewhere. The common factors are a small size, an herbivorous (? or insectivorous) diet, a high reproductive potential and a polymorphism which permits quick adaptation to the different population structures found under different population densities.     

Observations on courtship,mating and sexual maturity in Portunus pelagicus (L., 1766) (Crustacea,Portunidae)

Summary

Larvae of Alpheus heterochaelis from North Carolina hatch from large eggs as advanced zoeae, usually moult three times, and exhibit almost no linear growth during a short (4 days at 25°c) larval development. Stage I lasts 6 hours at most and is sometimes skipped; III lasts about twice as long as II. Individuals simultaneously exhibiting characteristics of Stage III and the postlarva were occasionally seen. The three zoeal stages and postlarva are described in detail and illustrated. Stages in embryonic and juvenile development and the hatching process are briefly described.

An ‘extended’ pattern of larval development, characteristic of most alpheid species, is described in a general way, and the ‘abbreviated’ development of A. heterochaelis compared to it. At hatching, A. heterochaelis larvae bear rudimentary pereiopods and pleopods; other structures are at the same level of development in both patterns, but subsequent morphogenesis is faster in A. heterochaelis. Larval development of Synalpheus spp., some of which exhibit extreme abbreviation or direct development, is briefly described with reference to the A. heterochaelis pattern.     

Synopsis and taxonomic revision of three genera in the snake tribe Sonorini

ABSTRACT

Delimiting species is a crucial goal of integrative biology, and yet can be misled by homoplasy and high levels of morphological variation. The snake tribe Sonorini contains three genera that have long confounded taxonomists: Chilomeniscus, Chionactis and Sonora. Dynamic colour evolution in this group, including rampant geographic variation in colour and colour polymorphism, has led to a chaotic taxonomy. We used mitochondrial and high-throughput nuclear data (ddRADseq) and complete taxonomic sampling of each genus to reconstruct phylogenetic relationships and systematically revise the genus. Our research revealed that Sonora is paraphyletic with regards to Chilomeniscus and Chionactis and that at least one species (S. semiannulata) is paraphyletic with respect to at least one other recognized species. Additionally, we found substantial undescribed genetic diversity within multiple species which is incongruent with morphological variation in coloration. Accordingly, we proposed synonymizing Chionactis and Chilomeniscus with Sonora, which has taxonomic priority over both genera. As we found genetic evidence that supported some of the historically delimited diversity within multiple taxa, we revised species-level taxonomy accordingly. This new taxonomy recognizes a revised genus of Sonora that contains 15 species of diminutive and often brightly coloured snakes that are distributed from central Mexico to north-western USA.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:45A553D8-6435-4E0A-84ED-DF31E2CCD872     

Host ranges of parasitoids (Hymenoptera: Braconidae and Ichneumonidae) reared from Epermenia chaerophyllella (Goeze) (Lepidoptera: Epermeniidae) in Britain,with description of a new species of Triclistus (Ichneumonidae)

The complex of parasitoids attacking larval stages of Epermenia chaerophyllella in Britain is outlined, and the host range of each of the species recorded (three braconids and four ichneumonids) is discussed. ‘Ecological’ factors, such as the behavioural similarity of unrelated hosts during the vulnerable parts of their life histories, seem to have been important in the evolution of the host associations of several of these parasitoids, even though they are koinobionts. A new species, Triclistus epermeniae Shaw and Aeschlimann, is described.