The life-history of Anoplocnemis curvipes F. (Coreinea,Coreidae, Heteroptera) A pest of fresh cowpea pods

Summary

Facts are given on the preoviposition and oviposition of mated females of A. curvipes. The size, shape, colour, incubation and hatching of eggs are described. The morphology and development of neanides at various stages are described—and compared with some data on the egg and neanide periods of a related species A. phasiana. Differences are pointed out between the neanides and adults of A. curvipes and the longevity and sex ratio of the adults are discussed.     

A new species of the genus Cytheridella (Crustacea,Ostracoda) from Nigeria,West Africa

Cytheridella tepida sp. nov., a freshwater ostracod, is described from Nigeria, West Africa. It has been compared with five extant species of the genus Cytheridella. Cytheridella tepida was collected from slow-flowing streams characterized by warm water. Some other ecological notes on its habitat are given.     

Biology of a tropical intertidal population of Cerithium atratum (Born, 1778) (Mollusca,Gastropoda)

The spatial distribution, population structure and secondary production of the gastropod Cerithium atratum were studied in the intertidal region of Engenho d'Água Beach in São Sebastião Channel on the northern coast of the state of São Paulo, Brazil, from May 1998 to April 1999. Twenty monthly samples were taken using a 0.25×0.25?m quadrat in each of two areas. Individuals showed a clustered dispersion pattern in both areas throughout the sampling period. Abundance and mean shell size were related to period of the year and to intertidal level, although no consistent pattern could be described when comparing the two sampling areas due to significant interaction between time and locality. Migratory events were evidenced by marked year-round variations in the frequency of individuals in the largest size classes. Thus, the size structure of this population could not be explained by recruitment and growth alone. Almost 90% of the intertidal population was represented by small individuals that recruited at the beginning of the sampling period (May to August 1998). The intertidal population was composed of annual cohorts formed by individuals recruited in different years. Each annual cohort could be divided into sub-cohorts with closely spaced recruitment periods in the same breeding season. The growth and annual P/B ¯ ratio (where P is the annual somatic production and B ¯ is the mean annual biomass) was estimated for the first year of life of recruits from 1998 occupying the intertidal region. Individuals may have an increment of up to 15?mm in shell length during the first year of life, but the growth was more pronounced in summer months. The high value of P/B ¯ (3.902) was a consequence of the dominance of small-sized individuals, which have a higher weight-specific increment than large-sized ones.     

Aspects of natural history in a sand boa,Eryx muelleri (Erycidae) from arid savannahs in Burkina Faso,Togo, and Nigeria (West Africa)

The ecology of West African arid savannah snakes is still poorly known, especially in regard to the fossorial species. Here, field data on distribution, morphometrics, habitat use and diet are reported for the sand boa Eryx muelleri (Erycidae) from three different countries, i.e. Burkina Faso, Togo and Nigeria. This snake was observed in 21 distinct localities, and a total of 39 individuals was recorded. The species is likely fairly common and locally abundant. Mean body length of snakes was similar among countries and between sexes, but males had proportionately longer tails than females. Body length was significantly positively correlated with both tail length and head length. Adult sex ratio was close to parity. Most of the specimens were found in well-vegetated spots with low percentage of bare soil. There were apparently both ontogenetic and intersexual dietary variations: (1) a single analysed juvenile fed upon a small-sized lizard, whereas adults fed considerably upon young rodents; and (2) females fed exclusively upon young rodents and males upon both lizards and young rodents. In conservation terms, the species is actively exported from Togo for the pet trade, and additional individuals may also be illegally collected in other countries.     

Nest sites of a northern population of an oviparous snake,Opheodrys vernalis (Serpentes,Colubridae)

Summary

The thermal characteristics of nest sites of the oviparous snake, Opheodrys vernalis, were studied in 1975 and 1976 near Cheboygan, Michigan. These characteristics were contrasted to the thermal regime of potential nest sites at shallow (1 cm) and deep (30 cm) locations in two contrasting habitats, open fields versus forest. On the basis of the great difference in temperatures of the two sites, it is postulated that oviparous reptiles at high latitudes or altitudes would tend to be restricted to open habitats where maintenance of higher incubation temperatures is more likely.     

Hip glands in a natural population of montane voles ( Microtus montanus )

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus   was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.     

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.     

Discovery of a large population of the rare winter stonefly Isocapnia mogila Ricker in the Mad River, California (Plecoptera, Capniidae)

Isocapnia mogila , a rare winter stonefly, is found in good numbers in Humboldt County, California. In the 50 years since this species was described, very few specimens were recorded from only 4 sites in California and Oregon. Emergence seems to be higher in the fall and early winter than in the late winter and spring.     

Life cycle and population structure of the terrestrial isopod Hemilepistus klugii (Brandt, 1833) (Isopoda: Oniscidea) in Iran

The life cycle and population structure of Hemilepistus klugii were studied in a population in Varamin, Iran. The population was sampled monthly (or fortnightly during the breeding season) from February 2008 to June 2009 and a total of 7015 individuals, comprising 1069 males, 1079 females and 4867 juveniles, were collected. As in other Hemilepistus species, five distinct phenophases, namely pair formation, gestation, hatching, growth and stationary, were recorded during the life cycle of H. klugii. The overall sex ratio was 1 : 1 but varied over time. Ovigerous females were observed only in April, indicating a seasonal and very short breeding period. With a short lifespan after breeding, females demonstrated true semelparity. The mean cephalothorax width for ovigerous/post-ovigerous females was higher in 2008 than in 2009. These females attained the largest size in the population throughout the year. The number of eggs per female ranged from 28 to 147 (mean ± SE, 78 ± 1.8). There was a positive correlation between female size and fecundity. Recruitment occurred in late April and resulted in the highest population density in this month, whereas the lowest densities were observed during November to January. Despite a high percentage of ovigerous females carrying undeveloped eggs (72.3%), intramarsupial mortality was low (3.5%).     

An extant, indigenous tortoise population in Baja California Sur, Mexico, with the description of a new species of Xerobates (Testudines: Testudinidae)

An extant, indigenous desert tortoise population is reported from the cape region of Baja California Sur, Mexico. This population is described and figured as a new species, Xerobates lepidocephalus , distinct from all other North American tortoises including Xerobates agassizii , X. berlandieri , Gopherus flavomarginatus , and G. polyphemus . Xerobates lepidocephalus , or the scaly-headed tortoise, whose range is known only from an extremely small area in the gulf-drainage mountains just south of La Paz, appears to be a peninsular relict whose closest living relative is probably X. agassizii . However, carpal bone affinities connote a close relationship between X. lepidocephalus and the Oligoeene species X. laticunea from Wyoming and Colorado, suggesting that the former species may be one of the more primitive contemporary tortoises of the Xerobates lineage. Such evidence indicates that X. lepidocephalus is not of vicariant origin resulting from the formation of the cape of Baja California. Scaly-headed tortoises likely ranged, and may yet be discovered, in other medium-elevation mountain ranges of the cape.     

Environmental influences on movements and distribution of a wild horse (Equus caballus) population in western Nevada,USA: a 25-year study

Wild horse populations in the American West have been heavily managed to regulate horse numbers since the inception of the Free-Roaming Wild Horse and Burro Act of 1971. The Montgomery Pass Wild Horse Territory (MPWHT) on the California/Nevada border is unique in the absence of human intervention there across the past 30 years. This has provided the opportunity to observe long-term patterns in the natural relationship between wild horses and their environment and to examine environmental impacts on the horse population and its activities, movements and distribution on the range. In this study multiple variables in the physical environment and in horse behaviour were monitored seasonally across 25 years beginning in 1987. Distinct summer (higher elevations) and winter (lower elevations) range use was characteristic for more than 60% of the population during the first 7 study years, with subsequent gradual but marked reduction in use of summer range. While approximately 20% of the population continued to annually use the historical summer range, the majority divided into two geographically and functionally separate subpopulations that resided year round in the historical winter range and adjacent areas on opposite sides of the MPWHT. Mountain lion predation on foals was restricted to the summer range, and exodus of horses from the summer range resulted in increased foal survival where horse subpopulations eventually resided. The long-term consequences of increased horse numbers in the MPWHT remain under continued study. The present study has shown that wild horses are highly adaptive and individually varied in response to environmental pressures. It has also demonstrated the value of long-term monitoring of wild horse populations to reveal underlying dynamics and their potential management implications.     

A subterranean population of Garra barreimiae (Teleostei: Cyprinidae) from Oman,with comments on the concept of regressive evolution

The presence of a hypogean population of the cyprinid fish Garra barreimiae in the Jabal Akhdar mountains in Oman is noted. Specimens killed within a very short while of capture from the wild had very poorly developed optic lobes. The optic lobes of twelve fishes that died after four months in the light were nearly as large as those in epigean fishes so substantial brain tissue regrowth had occurred in that time. No development of the eye or optic nerve was detected. The eye remains in an embryonic condition close to the brain stem on the floor of the orbit.

The concept of regressive evolution is considered to be invalid because it is unfalsifiable. The epigenetic effect of heterochrony is considered to be more appropriate vehicle to explain the convergent evolution of cavernicolous fishes.     

A new species of Protocladorchis (Paramphistomidae,Dadaytrematinae) from Pangasius nasutus (Bleeker, 1863) in Thailand

Protocladorchis chinabutae sp. nov. from Pangasius nasutus in Thailand differs from Protocladorchis burmanicus mainly in the size, shape and position of the testes and from P. pangasii in body shape, egg size and the shape of the pharyngeal sacs. The genus has not previously been reported from Thailand.     

Evidence of a parasite protist in Eurhomalea lenticularis (Sowerby, 1835) (Mollusca: Bivalvia): A case of intraoocytarian parasitism

In the present paper a microsporidian parasitic protist is described and characterized; it was observed in oocytes of Eurhomalea lenticularis Sowerby. The clams were obtained in Algarrobo, Chile (33°20′S, 71°40′W). The observations were made on 5?µm sections of female clam gonads, processed by routine histological techniques with ARTETA trichromic stain. According to the parasite's characteristics, it is established that the microsporidian protist is related to the genus Steinhausia (Chytridiopsidae). Microsporidian prevalence reached 20.6% (n?=?34) in summer months, but there was no evidences of cell damage in the oocyte of the host; in a total of 66 female clams, a 10.6% of infection was detected between December 1995 and August 1996. The infection intensity showed that 77.4% of the infested acini had single parasitized oocytes, and 88.0% of total oocytes parasitized contained only one cyst in the cytoplasm.     

A revision of Neobenedenia Yamaguti, 1963 (Monogenea: Capsalidae) including a redescription of N. melleni (MacCallum, 1927) Yamaguti, 1963

Neobenedenia Yamaguti, 1963, a genus of capsalid (benedeniine) monogeneans lacking a vagina, is redefined. The generic diagnosis is amended to include previously unused characters like the path of tendons in the haptor from extrinsic muscles in the body, the presence and form of a marginal valve, the shape of the anterior attachment organs, the arrangement of musculature at the posterior (proximal) end of the penis sac and the presence of a pair of sphincters in the female reproductive tract. On this basis, the generic composition is reduced from 10 to six species. Species considered valid are: N. melleni (MacCallum, 1927) Yamaguti, 1963; N. adenea (Meserve, 1938) Yamaguti, 1963; N. isabellae (Meserve, 1938) Yamaguti, 1963; N. longiprostata Bravo-Hollis, 1971; N. muelleri (Meserve, 1938) Yamaguti, 1963; N. pacifica Bravo-Hollis, 1971. Neobenedenia girellae (Hargis, 1955) Yamaguti, 1963 and N. paragueraensis Dyer, Williams and Bunkley-Williams, 1992 are considered synonyms of N. melleni. Species formerly ascribed to Neobenedenia, namely N. manilae Velasquez, 1982 and N. vermiculariacola Gupta and Khanna, 1975 are considered species inquirendae. A key to valid species is presented. The type species, N. melleni, is redescribed based on the original specimens of MacCallum and N. isabellae is redescribed based on material from the type locality. Since no types of N. melleni were designated, a lectotype and paralectotypes are assigned. The problem of host designation and locality for the types of N. melleni sensu MacCallum is discussed. A study of more than 80 specimens now considered to be N. melleni has permitted comments on its apparent variety of forms and its low host-specificity according to the current revision. N. melleni is now recorded from over 100 species of teleosts in more than 30 families from five different orders. Material reported previously as N. melleni off Chile from Seriola mazatlana, Thunnus thynnus orientalis and Seriola sp. are identified here as Benedenia seriolae (Yamaguti, 1934) Price, 1939. The host-specificity and geographic distribution of species in the revised genus is discussed.     

Aspects of the biology of a population of the cosmopolitan brittlestar Amphipholis squamata (Echinodermata) from the Firth of Forth,Scotland

In the Firth of Forth, Amphipholis squamata has continuous brooding, and pulsed breeding and recruitment, with highest numbers of brooded embryos and newly released juveniles occurring in the summer months. The estimated size of maturity was 1·5 mm disc diameter although the majority of reproductive output came from individuals of between 2·00–2·99 mm disc diameter. Brittlestar size and season had significant effects on embryo production. Embryos of different developmental stages were present in the bursae of the same individual, and newly spawned embryos and those of a potentially releasable size were present each month. The majority of juveniles apparently emerge at a disc diameter of between 0·8–1·2 mm.

Brittlestars were found with full stomachs throughout the year but a peak of feeding was recorded during summer when growth and seawater temperatures were highest. Stomach analyses indicated that almost all animals (99·4%) ingest fine particulate matter but a relatively wide range of plant and animal food items was also identified. Approximately 3% of this Scottish population of A. squamata was infested by the ectoparasitic copepod Cancerilla tubulata.     

Attack and brood production by the Douglas-fir beetle (Coleoptera: Scolytidae) in Douglas-fir, Pseudotsuga menziesii var. glauca (Pinaceae), following a wildfire

In 1994 ground fire ignited in forests of Douglas-fir, Pseudotsuga menziesii var. glauca (Mirb.) Franco, on Beaver Mountain, Utah. The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, attacked a range of moderately fire-injured host conifers in 1995. Logistic regression models run for 1995 data illustrated that 1 year after the fire event the Douglas-fir beetle selected and attacked large-diameter Douglas-fir with 60%-80% bole char, 60%-80% crown volume scorch, and 50%-70% probability of mortality due to fire. In 1996 beetle preference shifted to smallerdiameter trees with lighter fire injury, because most large, fire-damaged conifers were colonized by beetles in 1995. Although beetle populations did not reach outbreak proportions outside the fire boundary, host selection shifted to green trees in 1997 along the burn perimeter. Log linear analysis indicated that increased brood production was conditioned by increased diameter and moderate fire damage to the trees.     

Aspects of the activity rhythm and population size of troglophilic mygalomorph spiders (Trechona sp., Dipluridae) in a quartzite cave in Minas Gerais,Brazil

Records of mygalomorphs inhabiting caves have increased in the past years. We present data on a population of Trechona sp. spiders, found in a quartizite cave in Diamantina, Minas Gerais, Brazil. The spiders and their retreats were marked, and this population was followed for 17 months. The population consisted of up to 100 individuals, comprising the worlds’ largest known cave-dwelling population of mygalomophs. The estimated population size (Jolly-Seber model) varied from 50.36 to 853.43, the latter considered much overestimated. We did not find individuals of Trechona sp. in the surrounding epigean areas. The number of spiders was higher in the entrance zone than in the other two zones (twilight and dark zones). We found that individuals at the entrance zone showed similar activity to a nocturnal spider, whereas the other two groups showed conspicuous differences from this pattern, spending longer periods without rest, on the sheet-web as a sit-and-wait predator.