Climatic signals in the life histories of insects:the distribution and abundance of heather psyllids (Strophingia spp.) in the UK

1. The population density and age structure of two species of heather psyllid Strophingia ericae and Strophingia cinereae, feeding on Calluna vulgaris and Erica cinerea, respectively, were sampled using standardized methods at locations throughout Britain. Locations were chosen to represent the full latitudinal and altitudinal range of the host plants.

2. The paper explains how spatial variation in thermal environment, insect life-history characteristics and physiology, and plant distribution, interact to provide the mechanisms that determine the range and abundance of Strophingia spp.

3. Strophingia ericae and S. cinereae, despite the similarity in the spatial distribution patterns of their host plants within Britain, display strongly contrasting geographical ranges and corresponding life-history strategies. Strophingia ericae is found on its host plant throughout Britain but S. cinereae is restricted to low elevation sites south of the Mersey-Humber line and occupies only part of the latitudinal and altitudinal range of its host plant. There is no evidence to suggest that S. ericae has reached its potential altitudinal or latitudinal limit in the UK, even though its host plant appears to reach its altitudinal limit.

4. There was little difference in the ability of the two Strophingia spp. to survive shortterm exposure to temperatures as low as - 15 degrees C and low winter temperatures probably do not limit distribution in S. cinereae.

5. Population density of S. ericae was not related to altitude but showed a weak correlation with latitude. The spread of larval instars present at a site, measured as an index of instar homogeneity, was significantly correlated with a range of temperature related variables, of which May mean temperature and length of growing season above 3 degrees C (calculated using the Lennon and Turner climatic model) were the most significant. Factor analysis did not improve the level of correlation significantly above those obtained for single climatic variables. The data confirmed that S. ericae has a I year life cycle at the lowest elevations and a 2 year life cycle at the higher elevations. However, there was no evidence, as previously suggested, for an abrupt change from a one to a 2 year life cycle in S. ericae with increasing altitudes or latitudes.

6. By contrast with S. ericae, S. cinereae had an obligatory 1 year life cycle, its population decreased with altitude and the index of instar homogeneity showed little correlation with single temperature variables. Moreover, it occupied only part of the range of its host plant and its spatial distribution in the UK could be predicted with 96% accuracy using selected variables in discriminant analysis.

7. The life histories of the congeneric heather psyllids reflect adaptations that allow them to exploit host plants with different distributions in climatic and thereby geographical space. Strophingia ericae has the flexible life history that enables it to exploit C. vulgaris throughout its European boreal temperate range. Strophingia cinereae has a less flexible life history and is adapted for living on an oceanic temperate host. While the geographic ranges of the two Strophingia spp. overlap within the UK, the psyllids appear to respond differently to variation in their thermal environment.

Life histories of plants.

Mode of access: Internet.

Hormone and Metabolite Profiles in Nesting Green and Flatback Turtles: Turtle Species with Different Life Histories

Herbivorous turtle, Chelonia mydas, inhabiting the south China Sea and breeding in Peninsular Malaysia, and Natator depressus, a carnivorous turtle inhabiting the Great Barrier Reef and breeding at Curtis Island in Queensland, Australia, differ both in diet and life history. Analysis of plasma metabolites levels and six sex steroid hormones during the peak of their nesting season in both species showed hormonal and metabolite variations. When compared with results from other studies progesterone levels were the highest whereas dihydrotestosterone was the plasma steroid hormone present at the lowest concentration in both C. mydas and N. depressus plasma. Interestingly, oestrone was observed at relatively high concentrations in comparison to oestradiol levels recorded in previous studies suggesting that it plays a significant role in nesting turtles. Also, hormonal correlations between the studied species indicate unique physiological interactions during nesting. Pearson correlation analysis showed that in N. depressus the time of oviposition was associated with elevations in both plasma corticosterone and oestrone levels. Therefore, we conclude that corticosterone and oestrone may influence nesting behaviour and physiology in N. depressus. To summarise, these two nesting turtle species can be distinguished based on the hormonal profile of oestrone, progesterone, and testosterone using discriminant analysis.

From a "Student" to a Lifelong "Consumer" : Constructions of Educability in Adult Students' Narrative Life Histories

The focus of this study was to examine the constructions of the educable subject of the lifelong learning (LLL) narrative in the narrative life histories of adult students at general upper secondary school for adults (GUSSA). In this study lifelong learning has been defined as a cultural narrative on education, “a system of political thinking” that is not internally consistent, but has contradictory themes embedded within it (Billig et al., 1988). As earlier research has shown and this study also confirms, the LLL narrative creates differences between those who are included and those who fall behind and are excluded from the learning society ideal. Educability expresses socially constructed interpretations on who benefit from education and who should be educated and how. The presupposition in this study has been that contradictions between the LLL narrative and the so-called traditional constructions of educability are likely to be constructed as the former relies on the all-inclusive interpretation of educability and the latter on the meritocratic model of educating individuals based on their innate abilities. The school system continues to uphold the institutionalized ethos of educability that ranks students into the categories “bright”, “mediocre”, and “poor” (Räty & Snellman, 1998) on the basis of their abilities, including gender-related differences as well as differences based on social class. Traditional age-related norms also persist, for example general upper secondary education is normatively completed in youth and not in adulthood, and the formal learning context continues to outweigh both non-formal and informal learning. Moreover, in this study the construction of social differences in relation to educability and, thereafter unequal access to education has been examined in relation to age, social class, and gender. The biographical work of the research participants forms a peephole that permits the examination of the dilemmatic nature of the constructions of educability in this study. Formal general upper secondary education in adulthood is situated on the border between the traditional and the LLL narratives on educability: participation in GUSSA inevitably means that one’s ability and competence as a student and learner becomes reassessed through the assessment criteria maintained by schools, whereas according to the principles of LLL everyone is educable; everyone is encouraged to learn throughout their lives regardless of age, social class, or gender. This study is situated in the field of adult education, sociology of education, and social psychological research on educability, having also been informed by feminist studies. Moreover, this study contributes to narrative life history research combining the structural analysis of narratives (Labov & Waletzky, 1997), i.e. mini-stories within life history, with the analysis of the life histories as structural and thematic wholes and the creation of coherence in them; thus, permitting both micro and macro analyses. On accounting for the discontinuity created by participation in general upper secondary school study in adulthood and not normatively in youth, the GUSSA students construct coherence in relation to their ability and competence as students and learners. The seven case studies illuminate the social differences constructed in relation to educability, i.e. social class, gender, age, and the “new category of student and learner”. In the data of this study, i.e. 20 general upper secondary school adult graduates’ narrative life histories primarily generated through interviews, two main coherence patterns of the adult educable subject emerge. The first performance-oriented pattern displays qualities that are closely related to the principles of LLL. Contrary to the principles of lifewide learning, however, the documentation of one’s competence through formal qualifications outweighs non-formal and informal learning in preparation for future change and the competition for further education, professional careers, and higher social positions. The second flexible learning pattern calls into question the status of formal, especially theoretical and academically oriented education; inner development is seen as more important than such external signs of development — grades and certificates. Studying and learning is constructed as a hobby and as a means to a more satisfactory life as opposed to a socially and culturally valued serious occupation leading to further education and career development. Consequently, as a curious, active, and independent learner, this educable but not readily employable subject is pushed into the periphery of lifelong learning. These two coherence patterns of the adult educable subject illuminate who is to be educated and how. The educable and readily employable LLL subject is to participate in formal education in order to achieve qualifications for working life, whereas the educable but not employable subject may utilize lifewide learning for her/his own pleasure. Key words: adult education, general upper secondary school for adults, educability, lifelong learning, narrative life history

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest): Black, green, and red abalones

All abalones belong to the genus Haliotis sensu latu, family Haliotidae. The 75 species known worldwide (Booloot ian et, al. 1962) are anatomically similar and all are adapted for attachment to hard substrates. Seven species are widely distributed along the coast of California (Cox 1962; Mottet 19781, of which several are important in the comercial and sport fisheries of the Pacific Southwest. (PDF has 19 pages.)

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic): Alewife/Blueback Herring

This profile covers life history and environmental requirements of both alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis), since their distribution is overlapping and their morphology, ecological role, and environmental requirements are similar. The alewife is an anadromous species found in riverine, estuarine, and Atlantic coastal habitats, depending on life cycle stage, from Newfoundland (Winters et al. 1973) to Soutn Carolina (Berry 1964). Landlocked populations are i n the Great Lakes, Finger Lakes, and many other freshwater lakes (Bigelow and Sch roeder 1953; Scott and Crossman 1973). The blueback herring is an anadromous species found in riverine, estuarine, and Atlantic coastal habitats, depending on life stage cycle, from Nova Scotia to the St. Johns River, Florida (Hildebrand 1963)