The occurrence of Podocotyle atomon (Rud., 1802)(Digenea), Bothriocephalus scorpii (Müller, 1776) (Cestoda), Contracaecum clavatum (Rud., 1809) (Nematoda) and Echinorhynchus gadi Zoega,in Müller, 1776 (Acanthocephala) in the five-bearded rockling,Onos mustelus (L.)

Summary

The variation in the incidence and intensity of infestation of the five-bearded rockling, Onos mustelus (L.) with Podocotyle atomon, Bothriocephalus scorpii, Contracaecum clavatum and Echinorhynchus gadi has been studied for a period of one year, on a shore at Mumbles Head, Swansea.

There is a general increase in the incidence and intensity of infestation by P. atomon and C. clavatum with increase in the length (age) of the host. With E. gadi and B. scorpii, however, infestation decreases in the larger fish.

The seasonal variations in the incidence and intensity of infestation with these parasites are influenced by tidal fluctuations, temperature and by the feeding habits and breeding cycle of the fish.

The frequency distribution of parasite specimens is also described and discussed.     

The occurrence of Parvatrema homoeotecnum James, 1964 (Trematoda: Gymnophallidae) in a population of Littorina saxatilis tenebrosa (Mont.)

Summary

Marking experiments, seasonal variations in the population density and observations on the breeding cycle indicated that healthy adult Littorina saxatilis tenebrosa (Mont.) migrate down to the lower supralittoral fringe in order to give birth to the young in July–August and in January–February. The young and adults then migrate up towards the upper supralittoral fringe. Specimens infected with Parvatrema homoeotecnum, unlike those infected with two other digenean species investigated, migrate in the same way as healthy specimens. This ensures that although initial infestation takes place in the lower supralittoral fringe, parasitized specimens occur throughout the supralittoral fringe. Only juvenile hosts, below 7·0 mm long and usually below 5·0 mm long are infected, highest percentages occurring in specimens measuring 1·1–2·0 mm long. The seasonal variations in percentage infection are corellated with the breeding cycle, growth, mortality and migration of the host.     

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.     

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.     

Haematozoans,mites and body condition in the oceanic island lizard Gallotia atlantica (Peters and Doria, 1882) (Reptilia: Lacertidae)

We studied relationships among blood haemogregarines (Apicomplexa), ectoparasitic mites (Ophyonissus; Acari: Trombiculidae) and an endemic lizard host (Gallotia atlantica, Lacertidae) on an oceanic islet (Alegranza, Canary Islands). We asked whether blood infection, mite load and body condition were related in lizard subpopulations at two contrasting habitats. Both haemogregarine prevalence (100%) and intensity of parasitism (>1) were strikingly higher than values found for congeneric lizards from the other Canary Islands. There were few differences between habitats in infection levels, suggesting low influence of habitat on parasite performance. Both mite prevalence and intensity were very high, though only prevalence differed between habitats (higher in the richest and climatically more sheltered site). Body condition in lizards did not differ significantly between habitats. We found no association among blood parasite load, mite infection and lizard body condition. Results are discussed in the context of parasite‐host relationships on small islands as compared to larger areas such as continents.     

Life history and host utilization pattern of a strepsipteran parasite (Insecta: Strepsiptera) on the Blissine bugs (Hemiptera: Lygaeidae) living under dwarf bamboo leaf sheaths

The blissine bug Macropes obnubilus, which lives aggregately under leaf sheaths of the evergreen dwarf bamboo, is infected by the strepsipteran parasite Blissoxenos esakii. To determine the ecological properties of the bug–strepsipteran system, we conducted field surveys of natural populations of Macropes bugs and Blissoxenos parasites. The parasitism rate of strepsipterans was high throughout the year and was significantly higher in female than in male bugs. Blissoxenos adult males emerged mainly in May, and neotenic adult females released triungulins in August. The triungulins invaded host nymphs, but subsequent larval development did not occur before the bugs matured. At most, two strepsipterans could mature in a host because of spatial limitations. The mortality of triply or more parasitized bugs was significantly higher than that of singly or doubly parasitized bugs, which survived longer than uninfected ones. The heavy strepsipteran infection profoundly affected the host population by causing host reproductive failure.     

Studies on Gasteroclisus rhomboidalis (Boheman.) (Coleoptera: Curculionidae)—a pest of the African ‘spinach’

Summary

Eggs of G. rhomboidalis are usually laid singly in separate excavations made with the snout of the beetle in either leaf petioles or tender portions of shoots of host plants, Amaranthus sp. At field temperatures fluctuating between 19°C and 30°C and in contact with water, eggs hatched in a mean of 2·8 days while unmoistened ones shrivelled up.

Beetle larvae bore and feed on the stele of host plants where development, up to adulthood, is completed in self-made larval galleries. On the average, the larvae are capable of consuming 40% and above of the cross-sectional areas of stems of infected host plants. In nature, multiple infection of host plants was quite common with 1–16 beetle larvae/plant rather usual. Consequently, the stem of virtually every healthy-looking host plant is internally traversed by larval galleries, at times even below ground level.

Adults bite their way out of the stem after a mean of 36·37 days from date of oviposition.

Larval damages to host plants are the gravest and bring about premature breakage and/or death of crops, stunted growth and reduced yield of the wanted leaf products.     

The biology of some Phyllonorycter species (Lepidoptera: Gracillariidae) mining leaves of oak and beech

Summary

The oak leaf miners P. quercifoliella and P. harrisella were encountered at first generation densities of 40 and 48 mines per 1000 leaves in 1968 and 1969 and second generation densities of 179 and 211 mines per 1000 leaves. The 1969 densities for the two generations of P. maestingella on beech were 54 and 118 mines per 1000 leaves. The mines on oak were found to be aggregated on certain trees but the reason for this was not discovered. There was also aggregation on certain leaves within a tree.

The moths had two generations of adults per year at Dunham, the first generation mines appearing on the leaves in June and the second generation mines in August. P. maestingella seemed to be slightly in advance of the oak species.

The sampling data provided estimates of the mortality through 1969. Larval interference and mine damage caused negligible mortality. Death due to unknown factors figured prominently in the early instars but in the later instars, especially during the second generation, parasitism was important. Leaf browning was an added source of mortality in the second generation as was overwintering.

Fifteen species of hymenopterous parasites were bred from Phyllonorycter on oak and eight from P. maestingella on beech. Among these were some new host records. T. ecus was the most common first generation parasite of oak mines and C. nephereus. E. latreillei, S. sericeicornis, C. diallus and C. vittatus figured prominently in the second generation parasite complex. E. cilla was the commonest parasite of both generations of P. maestingella.     

Metazoan parasites of Calophysus macropterus (Siluriformes: Pimelodidae) in the Acre and Iaco rivers in the western Amazon region of Brazil: diversity,similarity and seasonal variation

ABSTRACT

The diversity, similarity and seasonal variation of metazoan parasite communities in Calophysus macropterus in the Acre and Iaco rivers, in the western Amazon (Brazil), was investigated. Parasites from 13 taxa were collected from C. macropterus in both rivers: four species of monogeneans, four nematodes, two cestodes, one digenean, one crustacean and one pentastomid. In hosts from the Acre river, Cucullanus pinnai predominated; while in hosts in the Iaco river, Monticellia amazonica predominated. The component communities of the parasites among the hosts in the two rivers presented high similarity (100%). Prevalence of Alinema amazonicum was higher in hosts in the Acre river; while the prevalence of C. pinnai was higher in hosts in the Iaco river and the mean prevalence and abundance of M. amazonica were higher in fish from the Iaco river. Regarding C. macropterus from the Acre river, infection levels by A. amazonicum were higher during the rainy season, while Demidospermus pinirampi only occurred in the dry season and Procamallanus (Spirocamallanus) inopinatus only occurred in the rainy season. In hosts from the Iaco river, infections by larvae of Anisakidae gen. sp. were higher during the dry season, while infection by Rudolphiella piracatinga and Sebekia sp. only occurred in the rainy season. However, P. (S.) inopinatus, Ergasilus callophysus, Ameloblastella unapi, Demidospermus luckyi, Demidospermus macropteri and D. pinirampi only occurred in the dry season. High similarity of the component communities of the parasite was observed between the rainy and dry seasons. These results suggest that factors other than location and seasonality were influencing the communities and infracommunities of the parasites found. Lastly, C. macropterus is a new host for almost 50% of the parasite species found. In addition, the results from the present study have expanded the geographical range of these 13 species of parasites to the western Amazon region.     

The parasites of the psyllidae—3. Some notes on the biology and host relationships of Parapsyllae-Phagus Adulticolus Robinson (Hymenoptera)

Abstract

Parapsyllaephagus Adulticolus Robinson (CHALCIDIDAE: Encyrtinae) is an endoparasite of the adults of Psylla melanoneura Förster and Psylla subferrigenea Edwards. The life histories and biology of the hosts and parasite are described. Parapsyllaephagus adulticolus has five larval instars, which feed selectively upon the developing internal genitalia of the host at first, and eventually, as the final instar, upon the whole of the abdominal viscera. Pupation within the psyllid is followed by emergence of the adult parasite through the posterior dorsal surface of the abdomen of the host. The effect of these activities upon the migration of the adult psyllid from a winter shelter plant to a summer host plant is discussed and a relationship between the stimulus to migrate and the state of development of the internal genitalia is postulated. Some aspects of the orientation of the parasite larva within the host and the phenomenon of larval reversal are discussed.     

A review of the genus Isaurus Gray, 1828 (Zoanthidea), including new records from Fiji

Summary

The first case is reported of a non-lethal interaction between a butterfly and tachinid which had little effect on host or parasite, and is discussed in its implications in relation to tropical tachinids and their hosts.     

LVIII.—On some new and curious Thysanoptera (Tubulifera) from Papua

Summary

Observations are made on the morphology of a polystomatid parasite recovered from Ptychadena mascareniensis in two areas of Uganda. Comparisons are made with other material from Zaire, Ethiopia and Uganda and a single taxon, Polystoma pricei (syn. P. africanum aethiopiense), is recognised. The present information on the morphological variation of the species suggests that P. pricei cannot be adequately separated from P. africanum and this latter designation takes precedence. The parasite is widely distributed with the following hosts and range: Bufo regularis in Liberia, Uganda and Ethiopia, Ptychadena mascareniensis in Uganda and Ethiopia, Ptychadena sp. in Zaire, and Rana angolensis in Ethiopia.

The systematics of the African species of Polystoma is reviewed and the close affinity of many of the taxa is recognised. Problems in the existing taxonomy of this group are discussed and a Polystoma africanum species complex is proposed.     

Figs (Ficus spp.) and fig-wasps (Chalcidoidea)

Summary

The host plant, trichobothria, male and female genitalia of Lestonia haustorifera China are discussed. The family Lestoniidae is closely related morphologically to the Plataspidae, more distantly related to the Scutelleridae, and unrelated to the Aphylidae.     

Some notes on the ecology of three milkweed bugs in India (Heteroptera: Lygaeidae)

Summary

Caenocoris nerii (Germar) is recorded for the first time in S. India, further distribution records of Spilostethus hospes (Fabricius) are noted, host plants and population trends of Spilostethus pandurus (Scopoli), S. hospes and C. nerii are recorded and discussed with reference to climate and altitude (with two tables and one figure).     

Two new species of Rhizorhina (Copepoda: Siphonostomatoida) from leptostracan and tanaidacean hosts

Summary

Two new species of parasitic copepods from the North Atlantic, Rhizorhina leptostracae associated with Nebaliella caboti, and Rhizorhina tanaidaceae from Leviapseudes hanseni, are described. Leptostracans and tanaids are new host groups for this genus. The systematic position of Rhizorhina is discussed.     

Gorgonolaureus muzikae sp. nov. (Crustacea: Ascothoracida) parasitic on a Hawaiian gorgonian,with special reference to its protandric hermaphroditism

Summary

Twenty-five specimens of a new ascothoracid parasite, Gorgonolaureus muzikae were found within cortical galls on specimens of a bathyal Hawaiian gorgonian, Placogorgia sp. These represent the first ascothoracid known from Hawaii. G. muzikae differs from its congener G. bikiniensis primarily in its larger size and details of setation. Five developmental stages are described and illustrated: the mature female, young female, late protander, protander, and nauplius. The protander is compared to species of Synagoga, and the characters distinguishing the two genera are specified. Sexuality in Ascothoracida is reviewed, and the life cycle of G. muzikae is reconstructed as follows: eggs and larvae are brooded within the carapace of a mature female; a bivalved, free-swimming male stage is postulated; after inseminating one or more established females it settles permanently on a host gorgonian; as the protandric male changes into a female, the carapace valves fuse and expand dorsally, the first and second antennae, thoracopods, penis, and abdomen become reduced, the dorsum of the second thoracomere becomes produced into a ‘horn’, and seminal receptacles appear in the thoracopods. The functional morphology of the second antennae, dorsal horn, and thoracopods is discussed, and it is suggested that G. muzikae may filter feed rather than be totally parasitic. The possibility that the large coxal setae represent vestigial epipods is discussed. Aspects of ecology, demography, and host specificity are briefly summarized. Wagin's (1976) biogeographical model of the provenance of Gorgonolaureus, based on outdated information, is rejected.     

The Biology and Development of Brachygaster minutus Olivier (Hymenoptera: Evaniidae), a parasite of the oothecae of Ectobius spp. (Dictyoptera: Blattidae).

Summary

Brachygaster minutus is a parasite of the oothecae of three species of British field-dwelling cockroaches belonging to the genus Ectobius. This species has previously received very little attention probably due to its restricted occurrence in Britain and the difficulties encountered in its collection. The life cycle and development of the parasite is described. The species is solitary in habit, the single larva overwintering within the ootheca as a final instar. The emergence of the adult the following summer is perfectly synchronized with the occurrence in the field of the particular cockroach species. Aspects of the mating and oviposition behaviour of the parasite are described.     

A new species of Deoterthron (Crustacea: Tantulocarida) ectoparasitic on a deep-sea asellote from New Zealand

Summary

A new species of the recently designated crustacean class Tantulocarida (Deoterthron megacephala sp. nov.) is described from New Zealand waters, ectoparasitic on an undescribed new species of the deep sea asellote genus Haploniscus, collected by epibenthic sledge at a depth of 1386 metres. Illustrations of the new parasite include the first scanning electron microscope photographs of a tantulocaridan. The genotype, Deoterthron dentatum Bradford & Hewitt has been re-examined to clarify certain structural features.