LXI.—Notes on insects collected in West Greenland by the Oxford University Greenland expedition, 1936. With descriptions of a new species of Angitia (Hymenoptera,Ichneumonidæ)by A. Roman,and of Fannia (Diptera,Anthomyidæ) by J. E. Collin

Summary

A population of Chaetogaster limnaei limnaei Gruffydd, living on various molluscs in the Worcester-Birmingham canal, was studied from February 1971 to February 1973 in the course of a detailed study of the digeneans parasitizing the molluscs.

The incidence of C. l. limnaei on each of its hosts was recorded for each month during the sampling period.

The incidence of the worms was high during the winter months on Physa fontinalis (and Lymnaea peregra) but low during the summer, and was high during the summer and low during the winter on Bithynia tentaculata.

It is postulated that this pattern of incidence may have been due to a migration of the worms from the pulmonate hosts to B. tentaculata in late spring, when the large pulmonates died after breeding, and a return migration to the pulmonates the following autumn.

There was found to be no association between the digeneans parasitizing the molluscs and the occurrence of the oligochaetes, and it is suggested that in this case the oligochaetes have no influence on the parasitic burden of the molluscs.     

Field studies of Cybocephalus nigriceps nigriceps (J. Sahlberg) (Coleoptera: Cybocephalidae) in Israel

Summary

Cybocephalus nigriceps nigriceps (J. Sahlberg) reproduces in Elat (the Arava region of Israel) during spring and summer. Eggs and larvae are present on date palms during these seasons only, whereas adults occur in the grove throughout the year. The adult population reaches its peak in mid-summer and decreases considerably during spring and autumn. Two main locations in which adults occur during the seasons, were found on date palm trees.

Due to the lack of reproduction and activity during autumn and winter, the predator takes almost no part in the biological control of the parlatoria date scale in these seasons.     

The armoured scale insects (Homoptera: Diaspididae) of avocado trees in Israel

Summary

Seven species of armoured scale insects infest avocado in Israel. Hemiberlesia lataniae (Signoret) and Abgrallaspis cyanophylli (Signoret) are the most abundant. Avocado seedlings become infested in the nurseries, thus serving as important sources for commercial grove contamination. Because larger diaspidid populations develop at the inside of the trees (as compared to their outside), and at height levels of 1·5–2·0 m (compared to 5·0–6·0 m), these regions were regularly sampled. Equal-area examinations of bark and leaf revealed that H. lataniae prefers the bark, A. cyanophylli the leaves. The populations of both scales undergo similar annual cycles on leaves, peaking during winter, ebbing in early summer. The specific settling pattern of most diaspidids on avocado leaves were figured. The somewhat-different settling sites of H. lataniae and A. cyanophylli apparently preclude competition when low numbers are present, but the former may be partially inhibited when large populations develop. Several predators and hymenopterous parasitoids attack the diaspidids, the parasitoids being most active in early summer. No economic injury to local avocado fruit by armoured scale insects has been reported in recent years. The reasons for this are discussed, and it is recommended that the present situation, in which no insecticides are used in avocado groves, be maintained.     

Biometry of brooding in seven species of amphipod (Crustacea) from the Clyde Sea area

Brood size was found to be correlated linearly with female body length in all species studied, except Ampelisca macrocephala, which is usually a single brooded species. Of the six multi-brooded species, Lembos websteri, Stegocephaloides christianiensis, Echinogammarus pirloti and Gammaropsis nitida produced small numbers of large eggs in the winter and large numbers of small eggs in the summer. In Bathyporeia pilosa larger numbers of smaller eggs were produced by the overwintering generation. In Corophium bonnellii, both maximum and minimum brood sizes were produced by the summer generation. The largest broods relative to female body size were produced by the smaller species. In L. websteri, C. bonnellii and B. pilosa mean female size was smaller in the summer than the winter generation.     

Secondary sexual characters in Celaenorrhinus and the delimitation of the genus (Lepidoptera,Hesperiidae)

Summary

Scent producing organs involving parts of the thorax as well as of the abdomen in males of Calaenorrhinus and some related genera are described. The unique character of abdominal pouches with scent hairs is applied to delimit the genus Celaenorrhinus Hübner, 1819, the only pantropical genus of the Hesperiidae. As a consequence, the genera Orneates Godman and Salvin, 1894, and Charmion de Nicéville, 1894, are placed in synonymy. Two species without secondary sexual characters are also considered to belong to Celaenorrhinus, viz., Plesioneura aurivittata Moore, 1865, and Plesioneura jao Mabille, 1889, the latter being placed in Celaenorrhinus for the first time. The evolution of the described scent organs is discussed in relation to their geographic distribution.     

Larval development of the coronuloid barnacles Austrobalanus imperator (Darwin), Tetraclitella purpurascens (Wood) and Tesseropora rosea (Krauss) (Cirripedia,Tetraclitidae)

The presence of embryos in the mantle cavity of A. imperator, T. purpurascens and T. rosea was monitored over two years. Tesseropora rosea showed a clearly defined breeding season in summer and early autumn. Seasonal breeding in A. imperator and T. purpurascens was less well defined, a small number of gravid individuals being present during most of the year. Breeding increased during the late autumn and early winter in A. imperator and during winter, spring and early summer in T. purpurascens. The larval stages of A. imperator, T. purpurascens and T. rosea are described from larvae reared in the laboratory. Separation of the larval stages between these species depends on fine morphological detail. Distinctive larval features permit the separation of coronuloid larvae from those of the other balanomorph superfamilies, but coronuloid nauplii resemble balanoid nauplii more than chthamaloid nauplii.     

Observations on an aggregation of the starfish Asterias rubens L. in Morecambe Bay,Lancashire, England

Summary

In the summer of 1976 a narrow, band-shaped aggregation of the starfish Asterias rubens occurred on widespread subtidal beds of Mytilus edulis in Morecambe Bay, Lancashire. Distribution of starfish along the band, which was moving towards the intertidal, was patchy and greatest densities occurred at the leading edge of the aggregation. In dense patches less than 50% of the starfish were actively feeding. The size distribution of the starfish was unimodal. Potential factors leading to the irregular summer season aggregations of A. rubens associated with superabundant food such as mussels are discussed. Observations on the scavenging whelk Buccinum undatum in the starfish aggregation are compared with observations from an area where there were fewer starfish.     

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.     

Population structure and breeding biology of the hairy crab Pilumnus vespertilio (Fabricius, 1793) (Crustacea: Brachyura: Pilumnidae) in southern Mozambique

The population structure and reproduction of Pilumnus vespertilio were studied for the first time in Mozambique. Random samples of crabs were taken monthly from January to December 2002 from a pebble area of Inhaca Island, southern Mozambique. A clear sexual dimorphism was observed in the present population with males reaching greater sizes than females. Sex ratio was female‐biased, and the monthly size–frequency distributions were often bimodal. The annual reproductive cycle of Pilumnus vespertilio was continuous with peaks of breeding in summer. Results suggest that embryonic development may be synchronized within the population as a result of the very high reproductive activity observed in summer. Juveniles are recruited mostly in winter in the study area.     

Two new Encarsia species (Hymenoptera: Aphelinidae) reared from eggs of Cicadellidae (Hemiptera: Auchenorrhyncha) in Argentina: an unusual new host association

Males of two undescribed Encarsia species were reared from eggs of two cicadellid species during a study of egg parasitoids of corn leafhopper, Dalbulus maidis (DeLong and Wolcott) in northwestern Argentina. Samples were collected during the summer of 2004–2007 using sentinel eggs, and several males of a new species of Encarsia (Hymenoptera: Chalcidoidea: Aphelinidae) were obtained. A single male of a closely related Encarsia species, also previously undescribed, was reared from an egg of another cicadellid on maize, Plesiommata mollicella (Fowler). These are the first records of any Encarsia species reared from eggs of Cicadellidae. The two new species are described as Encarsia dalbulae Polaszek and Luft Albarracin sp. nov., and Encarsia mollicellae Polaszek and Luft Albarracin sp. nov.     

Seasonal reproduction in deep-sea Crustacea (Isopoda: Asellota)

A collection of Crustacea Isopoda (suborder Asellota) from a 10-year sampling programme in the Rockall Trough, NE Atlantic (54°40′N, 12°15′W) was analysed for evidence of breeding seasonality. No evidence of seasonal activity was found — adults and newly released juveniles were present throughout the year — but there was a strong seasonal pattern for breeding intensity. A significantly higher proportion of females was brooding during the winter months (25%) compared to the summer (5%), and the percentage of females brooding varied significantly with depth. The breeding pattern was synchronized to the seasonal deposition of organic detritus known to occur during the summer in the NE Atlantic. There were more newly released juveniles in samples during the summer than during the winter, with most females appearing to release their young at the time the deposition began. This deposition appears to be a major seasonal factor dominating the life-cycles of most benthic species in the Rockall Trough. Juvenile settlement for a range of taxa (echinoderms, molluscs and crustaceans) occurs while the detritus is present and most species maximize vitellogenesis at this time.     

Temporal changes in burrow structure of the thalassinidean ghost shrimps Trypaea australiensis and Biffarius arenosus

The thalassinidean ghost shrimps Trypaea australiensis and Biffarius arenosus are dominant burrowing macroinvertebrates of soft‐sediment habitats in Western Port, Victoria, Australia. Burrow structure has been described for both species but little is known about how the burrows change over time. This study used resin casting to investigate temporal variation by making burrow casts each month over a 12‐month period. It was found that the overall burrow morphology of both T. australiensis and B. arenosus was consistent over time, but in the warmer months (summer and spring), both species constructed burrows that were deeper and of greater volume than burrows constructed in winter and autumn. Possible reasons for this variation are discussed.     

Natural history of Kermesidae (Hemiptera: Coccomorpha) in Israel

Aspects of the biology and life history of six Kermesidae species were studied in Israel between the years 2010 and 2013, namely five species of Kermes Boitard: Kermes echinatus Balachowsky, K. greeni Bodenheimer, K. hermonensis Spodek & Ben-Dov, K. nahalali Bodenheimer and K. spatulatus Balachowsky and one species of Nidularia, N. balachowskii Bodenheimer. All six species are oviparous, bi-sexual, univoltine and oligophagous on Quercus spp. (Fagaceae). The five Kermes species spend the winter, summer and autumn as first-instar nymphs, while it is the mated adult female of N. balachowskii that occurs during this period. The geographic distribution and host trees in Israel are reported for each of the six Kermesidae species. Information about associated ant fauna is also discussed.     

A collection of fieldmice from Rathlin Island Northern Ireland

Summary

During the summer of 1963 trapping was carried out on Rathlin Island for Apodemus sylvaticus. The fieldmice caught were significantly larger than those of the Irish mainland. This form possibly approximates to the Hebridean complex, the status of which is not at present clearly understood and it is felt that subspecific rank should be withheld until further collections are made.     

Survival and reproduction of the mussel Xenostrobus securis (Lam.) (Mollusca: Bivalvia: Mytilidae) in a Western Australian estuary

Summary

The Swan estuary is subject to extreme temporal and spatial variations in salinity. Downstream populations of the mussel Xenostrobus securis (Lamarck, 1819) are exposed to a seasonal range from 1·5‰. Cl to 20·0‰. Cl. In summer the estuary is progressively filled with saline water from the sea; in winter it is flooded by fresh river run-off water from the heavy and concentrated winter rains. The autumn fall in salinity is usually very rapid and constitutes a severe physiological shock for organisms inhabiting the estuary.

The physiography and hydrology of the Swan estuary are described. Experiments are reported on the salinity tolerance and behavioural responses to salinity stresses of adult mussels and larval stages.

Adult mussels show no ability to osmoregulate (except possibly at very low salinities). They can tolerate environmental chlorinities at least as high as 31‰. Cl and can withstand sudden dilutions from at least 18‰. down to 1‰.. They are capable of survival at 1‰. for many months.

Closure of the shell valves in response to sudden dilutions of the medium is a behavioural mechanism minimizing physiological shock. Adult mussels remain inactive with the valves closed indefinitely at chlorinities below 2‰.. However, the internal body fluids of the mussels become isotonic with the medium after a few days. Adult salinity tolerance and behavioural responses are sufficient to meet the conditions occurring in the estuary, and adult salinity tolerance is unlikely to limit distribution of the species.

In laboratory dishes eggs may be successfully fertilized, and normal cleavage occurs in water between about 8 to 9‰. and 17·5‰. Cl. This tolerance range of developing larvae imposes upstream limits on the distribution of the mussel and precludes any possibility of larval dispersal between adjacent estuaries by way of the sea.     

Filth inhabiting flies of Dacca city

Summary

Information obtained about the association of various flies with different types of filth in Dacca city, their life histories, food preference of the larvae, and the seasonal changes of their population has been recorded.

The filth of Dacca city has been classified into the following eight categories for the present work. (1) Human excrement, (2) cow dung, (3) manure heaps, (4) garbage and kitchen refuse, (5) decaying fruits and vegetables, (6) carrion, (7) rotten fish and meat, and (8) municipal sewage and other liquid waste.

In total nine fixed areas in different parts of the city were visited regularly to collect adult flies, or their eggs or larvae.

The association of various flies with the above eight types of filth has been discussed.

The duration of the life cycle from oviposition to emergence of the adults was recorded for five species of Psychoda, seven species of Musca, one species of Calliphora, two species of Chrysomyia, two species of Lucilia, and three species of Sarcophaga, during summer and winter.

Food preferences of the larvae of two common species of Musca, two species of Sarcophaga, one species of Lucilia, one species of Calliphora, and two species of Chrysomyia have been recorded.

The trend of the seasonal variation of the various fly populations have been discussed.     

Demographic characteristics,seasonal range and habitat topography of Balkan chamois population in its southernmost limit of its distribution (Giona mountain,Greece)

The annual range of Balkan chamois (Rupicapra rupicapra balcanica) in Giona mountain was found to be 5502 ha, with a low population density (2 individuals/100 ha). Seasonal range patterns varied significantly, with a minimum extent in summer and a maximum in winter (30% and 79% of the annual range, respectively). Summer stress and the rutting period might be associated with the observed aggregated distributions during the summer and autumn (core areas of 28% and 22% of seasonal ranges, respectively, defined after the Fixed Kernel Density Estimator). Chamois were found to use significantly lower altitude habitats in winter (1212 m) than in summer (2223 m), and significantly steeper slopes in winter (35°); aspect was not found to have a significant effect on habitat use. Population structure consisted of kids (21%), yearlings (8%), females (35%) and males (36%). Conservation management for the species should consider poaching, livestock competition and global warming.     

Two species of caligid copepods (Crustacea) parasitic on marine fishes of Venezuela,with discussion of Metacaligus Thomsen, 1949

Summary

O, I and II group flounders showed a regular increase in length and weight between April and September, but did not grow during the winter months. These immature fish showed highest condition factors and calorific values in summer and lowest in winter. III and ? IV group flounders had highest condition factors and calorific values in winter prior to spawning and lowest when they returned to the estuary as spents in April. Males matured towards the end of their third year and females towards the end of their fourth. Gonad development started in October and peak gonad weights were attained in November (males) and February to April (females).

Diurnal variations in the numbers of fish were very marked on the Sleek of Tarty where larger numbers were caught at night. Little diurnal variation was noticeable on the Forvie Bank mud flat.

Largest numbers of flounders were recorded between May and September when the population was 50–100 times larger than the winter low (January to March). Estimates of the total population size are given, based on observed densities on underwater transects.

Seasonal changes in the population of flounders on the intertidal mud flats were influenced by four major migrations:

• (1)A spring immigration (April and May) of immature (except the O group) and spent fish, the spent females being present in significantly greater numbers than males.

• (2)O group flounders entered the estuary in late June early/July, approximately two months later than the immigration of O group plaice.

• (3)A proportion of III and ? IV group flounders left the mud flats in July and tagging data suggested that they left for the sea.

• (4)The winter emigration of all age classes started in October and continued through the winter, leaving a small population composed mainly of O group and maturing fish. Cormorants preyed mainly on I and II group flounders in winter and probably accounted for the low numbers of these age groups at this time.

     

Survival and reproduction of the mussel Xenostrobus securis (Lamarck) (Mollusca; Bivalvia; Mytilidae) in a Western Australian estuary. Pt. II: Reproduction,growth and longevity

Summary

Growth, longevity and breeding characteristics of populations of the mussel Xenostrobus securis in the Swan Estuary are remarkably variable, both between one year and another and between upstream and downstream localities. These characteristics and their variability may be accounted for by the species' physiological responses and limitations to variable salinity conditions. The Swan Estuary is subject to extreme temporal and spatial variations in salinity. Temperature has only a secondary significance on the biology of the mussel in this estuary.

Activity including growth is inhibited at chlorinities below 2‰. This occurs each winter during the discharge period. At Crawley (downstream) the discharge period rarely lasts more than a few weeks in mid winter, but at upstream limits of the estuary (e.g. Barker Bridge) it is highly variable and may last as long as seven months. Consequently the period of no-growth which corresponds to the discharge period varies between downstream and upstream populations and the total annual growth increment varies accordingly. Similarly the duration of the no-growth period and the total annual growth increment varies from year to year at upstream localities.

At Crawley mussels live only one year. At that locality there is almost total mortality of adults soon after spawning. The relationship of the post-reproductive mortality to intensity of reproductive effort is discussed. At Barker Bridge heavy post-reproductive mortality was not observed and animals may live two years or more. This greater longevity at Barker Bridge is considered to have survival advantage for the population which is living in an unstable and inconsistent environment. Downstream conditions are more seasonally regular and the populations there can rely on having optimal conditions each year.

Spawning begins at the downstream end of the estuary in November or December when the chlorinity rises to the critical lower limit for larval development (8 to 9‰. Cl). A wave of spawning moves up the estuary as the summer progresses, following the zone of optimal salinity conditions. It does not reach Barker Bridge until February or March. In 1964 the chlorinity did not reach the lower limit for larval development at Barker Bridge and no spawning or spatfall occurred there.

It is considered that X. securis is physiologically well adapted for persistence in an estuarine environment characterized by variable and unstable salinity conditions.