Some aspects of the biology of the hedgehog (Erinaceus europaeus L.) in the Manawatu,New Zealand

In a study area of 16.3 ha of dairy pasture and pine plantations in the Manawatu region of the southern North Island, 150 hedgehogs were marked and 356 recaptures recorded between 1 January 1970 and 24 June 1971. Population density was estimated at between 1.1/ha in winter and 2.5/ha in summer and autumn. Only 11 females and 5 males were considered to be residents, and these used overlapping feeding ranges of similar extent. Concentrations of food organisms became foci of hedgehog activity. During winter, when an estimated 20% of the population died, movement was restricted to the vicinity of the nest site; the hedgehogs hibernated fitfully during July‐October. The breeding season as such extended at least from November to March; some breeding activity was observed in most months, however. The average life span of adults was 1.97 years. The causes of 6 natural deaths and the incidence of abscesses and external parasites were noted.     

Observations on the genus Bosmina in New Zealand

Summary The consideration of specimens from many localities in New Zealand shows that the genus Bosmina is represented by but a single species. This species is maintained to be B. meridionalis by the author. Dorsal incisures are shown to occur on the mucro in juvenile females which suggests the possible identity of this species with B. hagmanni Stingelin. Should the above species prove to be identical the specific name meridionalis is shown to take precedence.

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Résumé L'examen de nombreux specimens pris dans plusieurs endroits de la Nouvelle Zéelande démontre que le genre Bosmina n'est représenté que par l'espèce B. meridionalis. Des incisions dorsales sont visibles sur le mucro chez les jeunes femelles, ce qui suggère l'idée que cette espèce est identique à B. hagmanni Stingelin. Si ces espèces sont vraiment identiques, le nom spécifique B. meridionalis doit avoir la préséance.

     

Observations on granulocyte peroxidase in New Zealand freshwater eels, Anguilla species

Peroxidase activity in the granulocytes of eels was investigated using o-tolidine, paraphenylene-diamine-pyrocatechol, and 4-chloro-l-naphthol as substrates, and cyanide, azide and aminotriazole as inhibitors. Most circulating neutrophils of Anguilla australis Richardson, 1848 and A. dieffenbachii Gray. 1842 showed no peroxidase activity at pH 7.6 and pH 9.0, but a few neutrophils, thought to be mature, were positive. Another granulocyte in the anterior kidney, spleen, parasitized gill tissue and, rarely, the blood contained a cyanide-resistant, azide-inhibited, peroxidase and was tentatively identified as the eosinophil. Neutrophils of A. anguilla (L.) showed granular peroxidase activity which was inhibited by cyanide. The eosinophil was not observed.
Absence of peroxidase from most circulating neutrophils in A. anguilla and A. dieffenbachii , and its pattern in the neutrophil precursors and mature neutrophils of A. anguilla , may be due to two morphologically indistinguishable granule types. Primary peroxidase-negative granules occur in precursors and immature neutrophils and secondary peroxidase-positive granules in mature neutrophils of all three eels. Circulating neutrophils in New Zealand eels seldom mature and are theretore peroxidase-negative, whereas A. anguilla neutrophils are mature and are usually peroxidase-positive.
Impairment of microbicidal activity in neutrophils lacking peroxidase is discussed.     

Multiple paternity in the European hedgehog

Previous observations have suggested that European hedgehogs Erinaceus europaeus are promiscuous, although there have been no direct studies of the mating system to confirm this. In this study, the genetic mating system of the European hedgehog was assessed by analysing mother–offspring groups using six polymorphic microsatellite loci. Evidence of multiple paternity was found in two of five litters analysed and therefore demonstrates the occurrence of polyandry in wild populations of hedgehogs.     

Evolution of sexual dichromatism in relation to nesting habits in European passerines: a test of Wallace's hypothesis

Wallace proposed in 1868 that natural rather than sexual selection could explain the striking differences in avian plumage dichromatism. Thus, he predicted that nesting habits, through their association with nest predation, could drive changes in sexual dichromatism by enabling females in cavity nesters to become as conspicuous as males, whereas Darwin (1871, The Descent of Man and Selection in Relation to Sex, John Murray, London) argued that sexual selection was the sole explanation for dichromatism. Sexual dichromatism is currently used as indicating the strength of sexual selection, and therefore testing Wallace's claim with modern phylogentically controlled methodologies is of prime interest for comparing the roles of natural and sexual selection in affecting the evolution of avian coloration. Here, we have related information on nest attendance, sexual dichromatism and nesting habits (open and cavity nesting) to male and female plumage conspicuousness in European passerines. Nest incubation attendance does not explain male or female plumage conspicuousness but nest type does. Moreover, although females of monochromatic and cavity nesting species are more conspicuous than females of other species, males of monochromatic and open nesting species are those with more cryptic plumage. Finally, analyses of character evolution suggest that changes in nesting habits influence the probability of changes in both dichromatism and plumage conspicuousness of males but do not significantly affect those in females. These results strongly suggest a role of nesting habits in the evolution of plumage conspicuousness of males, and a role for sexual selection also in females, both factors affecting the evolution of sexual dichromatism. We discuss our findings in relation to the debate that Darwin and Wallace maintained more than one century ago on the importance of natural and sexual selection in driving the evolution of plumage conspicuousness and sexual dichromatism in birds, and conclude that our results partly support the evolutionary scenarios envisaged by both extraordinary scientists.     

Observations and comments on the body temperatures of some New Zealand reptiles

Abstract

Rectal body temperatures (BTs) of tuataras (Sphenodon punctatus) and of endemic, ovoviviparous gekkonid lizards—mainly Hoplodactylus maculatus (=H. pacificus) and Heteropholis manukanus—were taken together with ambient temperatures during early summer 1970 in areas of central New Zealand. The results, combined with earlier data, enable a number of conclusions to be drawn. (a) The preferred body temperature of heliotherm reptiles is best deduced from the mode of rectal BTS taken in the field, but that of non-heliotherms, when unimodal, from the median or mean. (b) Among Gekkonoidea, specific thermal relations are highly variable in several ways. (c) Sphenodon foraged on cool nights at BTs of 10.5–12.5°c, yet basked in the forest by day at BTs up to 24°c; in pasture it apparently basks within the burrow entrance. (d) Similarly, H. maculatus foraged at night at BTs of 10–13°c, but by day thermoregulated at BTs up to 33°c by ‘indirect basking’ (under thin cover) or ‘protected basking’ (in crevices penetrated by solar radiation). The average BT of females was 2°c higher than that of males, presumably because many females were gravid. (e) H. manukanus is (tertiarily) diurnal, and thermoregulated by basking up to a BT of 31 °c. Towards evening it apparently cooled down voluntarily. (f) Whereas a high daytime BT probably assists digestion in nocturnal foragers, a voluntary low night-time BT in diurnal reptiles may help to conserve energy.     

Observations on the haematology and oxygen transport of the New Zealand fur seal,Arctocephalus forsteri

Abstract

Red cell count, haemoglobin concentration, haematocrit, mean cell volume, and mean cell haemoglobin concentration were recorded for the fur seal Arctocephalus forsteri (Lesson). The data did not indicate haematological adaptations for deep diving nor for extended periods of submergence. Two distinct haemoglobin types were isolated from the red cells by electrophoresis. The oxygen affinity of the blood was low as measured by half-saturation values (p50) of 42.3 mm Hg at pH 7.1 and 26.2 mm Hg at pH 7.4 and 37°c. The low oxygen affinity was mediated by erythrocytic 2,3-diphosphoglycerate, and on this basis a high turnover of oxygen to the tissues is postulated. The role of the blood in oxygen transport appears to be suited for feeding near the surface rather than by deep diving.     

Distribution and food habits of the slender smoothhound,Gollum attenuatus,from the waters around New Zealand

Three hundred and seventy-three females and 385 malesof Gollum attenuatus were caught with bottom longlines from the Challenger Plateau, Wanganella Bank and Three Kings Ridge around New Zealand. The sharks ranged in size from 440 to 1092 mm TL for females and 442 to 1067 mm TL for males. Catch rates (number of fish per 100 hooks) were 0.41 for the Challenger Plateau, 0.14 for the Wanganella Bank, and 4.52 for the Three Kings Ridge. The sex ratio was 1:1. In terms of 100-m depth intervals,G. attenuatus was most abundant in 500 to 599 m depths. There was a marked decrease in catch rates with increased distance of the hooks from the bottom. Stomachs contained such varied items as sharks, teleost fishes, gastropods, squids, octopi, decapods, isopods, brittle stars, and human garbage. The data in this study suggest thatG. attenuatus consumed, in order of importance, fishes and crustaceans.     

Observations on the biology of Apatopygus recens (Echinoidea: Cassiduloida) around New Zealand

The biology of the New Zealand cassiduloid echinoid Apatopygus recens is reviewed in terms of its geographical distribution, sediment relationships, and associations with other echinoids. Observations were also made on the density and size-frequency distribution of an A. recens population at Croisilles* Harbour, Tasman Bay, and on the burrowing and feeding behaviour of specimens from this locality in an aquarium.
A. recens is a rapid and continuous deposit feeder which burrows completely beneath the surface of the coarse sediments with which it is characteristically associated. The construction of a respiratory burrow to the sediment surface was not observed and the species appears to rely entirely on an adequate interstitial water flow for its respiratory requirements. Two 24 mm long specimens each defaecated an average of 0·76 g dry wt of sediment/h which at the Croisilles Harbour habitat was equivalent to a population ingestion rate of about 7·6 g dry wt of sediment/m²/h.     

The importance of sand albedo for the thermal conditions on sea turtle nesting beaches

At Ascension Island and Cyprus, major nesting areas for green turtles ( Chelonia mydas ) in the Atlantic and Mediterranean, respectively, visual inspection shows some beaches are light in colour while others are darker. We objectively measured the albedo of the sand on different beaches, i.e. the percentage of the incident solar radiation that was reflected from the sand surface. At sites where albedo was recorded, we also measured the temperature of the sand at nest depths. At both rookeries, the sand temperature was markedly higher on darker beaches due to greater absorption of the incident solar radiation over the diurnal cycle. Temperature loggers buried at nest depths revealed seasonal changes in temperature on both islands, but showed that the lowest temperatures found on the darker beaches rarely dropped below the highest temperatures on the lighter beaches. Sea turtles exhibit temperature-dependent sex determination. Since sand albedo is a major avenue for the production of a range of incubation temperatures on both islands, it will also have profound implications for hatchling sex ratios. In comparison with both Ascension Island and Cyprus, for samples collected from sea turtle rookeries around the world there was an even greater range in sand albedo values. This suggests that sand albedo, a factor that has previously received little consideration, will have profound implications for nest temperatures, and hence hatchling sex ratios, for other populations and species.     

Observations on the feeding, growth rate and habits of newly settled Octopus cyanea

This paper records observations on the behaviour of Octopus cyuneu caught in Hawa shortly after settlement from the plankton. The young animals rapidly establish homes on the bottom and defend these against their own species. Of a variety of food offered, crabs were most frequently (nearly always) taken; the animals always took the prey home to eat it. Records of diurnal activity show morning and evening peaks as in adults. There was a steady 2–3.5% daily increase in weight over the first six months (July-January) after settlement     

Effects of agricultural development on processing of tussock leaf litter in high country New Zealand streams

1. We compare the rates and mechanisms of processing of tussock (Chionochloa spp.) leaf litter in six New Zealand streams draining grassland catchments that contrast in the extent to which they have been developed for pasture. 2. Rates of processing, measured as rate of weight loss of leaf packs and rate of leaf softening, were at the slow end of the spectrum for vascular plant processing. Processing was faster at developed sites, mediated mainly through the influence of oxidized nitrogen concentration on microbial activity. 3. Few invertebrate shredders colonized leaf packs and it is unlikely that invertebrates had an appreciable effect on leaf processing in our study streams, which do not effectively retain leaf litter. Very small headwater tributaries appear to retain leaf litter and possess a more abundant shredder community. 4. Measures of leaf processing in our six streams were significantly correlated with Petersen's (1992) RCE score of stream condition. We discuss the potential for using rate of leaf litter processing as a method of bioassessment. 5. Even the most degraded stream in our study is classed as ‘good’ using the RCE inventory system. Human impact in the Taieri River is relatively small compared with the degradation observed in some parts of the world.