Per-Olof Wickman

ABSENCE OF TRADE-OFFS BETWEEN SEXUAL SIZE DIMORPHISM AND EARLY MALE EMERGENCE IN A BUTTERFLY'

Protandry, here defined as the earlier emergence of males, is a common feature in life histories and could be the result of sexual selection on males to maximize matings, or alternatively an incidental by-product of other selection pressures on the sexes. If protandry is selected for per se, theory predicts that it should be associated with seasonal environments where there is little overlap between generations. The degree of protandry should be insensitive to environmental conditions. Moreover, on the assumption that males and females grow at the same rate as larvae, a trade-off between development time and size is expected to result in a strong association between protandry and female-biased sexual size dimorphism. These predictions were tested by a combination of comparative and experimental studies on five populations of the speckled wood butterfly, Pararge aegeria, from central and south Sweden, England, Spain, and the island of Madeira. Protandry was associated with seasonal environments, as it was only exhibited in the three northernmost populations. Protandry in these populations remained largely constant in a variety of temperatures, both under direct development, when protandry results from a sex difference in development time through the egg, larval, and pupal stages, and under diapause devel- opment, when it results from a sex difference in pupal development time only. These results indicate that protandry is selected for per se through sexual selection in seasonal environ- ments. Similar female-biased size dimorphism occurred in protandrous and non-protan- drous populations alike, and hence sexual size dimorphism in P. aegeria is not a result of selection for protandry, nor the causal factor behind protandry. Protandry and sexual size dimorphism appear to be largely decoupled traits in the life history evolution of P. aegeria. This is achieved by means of variation in pupal developmental time and variation in the relative growth rates of the sexes. Variation in growth rates is likely to be a general phe- nomenon and may make possible independent optimization of size and development time (age at sexual maturity), and accordingly influence expected patterns of size-related trade- offs.

SEXUAL SELECTION AND BUTTERFLY DESIGN-A COMPARATIVE STUDY

Temperate butterflies of 44 species were examined to determine if their mating system (perching and patrolling) affected flight design. To control for spurious effects due to ancestry, 25 of these species were assigned to eight contrasts within which a change in mating system had occurred. In perching species sexual selection was predicted to favor traits associated with high acceleration ability and speed, while in patrolling species traits associated with flight endurance were predicted. In conformance with these expectations males of perching species had larger thorax/body mass ratios, higher wing loadings, and higher aspect ratios than patrolling species. The male mating system affected females in the same direction in the same variables as males. This could be explained by a genetic correlation with males. When removing the covariance between the sexes, only male design was explained by the mating system. The mating system was also associated with different degrees of sexual dimorphism in wing size. This supported the hypothesis that male design was affected by the mating system.

Abdomen size, body size and the reproductive effort of insects

Scaling of abdomen size to body size is examined in seven species of Papilionoidea and in one species of Diptera. In all these insects abdomen size shows a positive allometric increase with body size, despite the increased cost of flight suggested by the scaling of wing area and muscle mass to body size. The consistent abdominal scaling pattern found, suggests that an increased reproductive effort with size should be expected in many butterflies, and probably in other insects as well.

Conflicts of interest: an indispensable element of education for sustainable development

A central concept introduced in the Nordic debate on sustainable development is ‘action competence’. The concept has been defined as a competence of learners, i.e. the ability to take into consideration the social factors and human conflicts of interest that lies behind environmental questions and sustainable development. The concern of this article is the role of such conflicts for making meaning in relation to sustainable development. With this aim, we analyze a series of interviews with seven high school students. Our analysis takes its point of departure in the works of Dewey and Wittgenstein. It shows that the dialogue partners in this study continuously put one another in the position of having to make communicative choices in the dialogue. Moreover, the choices facing these dialogue partners can be translated into human conflicts of interest of a broader kind. A conclusion we draw from our work is that value judgments dealing with human conflicts of interest are a foundation upon which the dialogue on sustainable development is constructed, and that they seem to be a prerequisite if the dialogue is not to come to a standstill. We discuss the consequences of this finding for education for sustainable development.

Induction as an Empirical Problem: How Students Generalize during Practical Work.

We examined how university students made generalizations when making morphological observations of insects. Five groups of two or three students working together were audio recorded. The results were analysed by an approach based on the work of Wittgenstein and on a pragmatic and sociocultural perspective. Results showed that students rarely made generalizations in terms of universal statements and they did not use induction or produced hypotheses for testing in an analytic philosophical sense. The few generalizations they made of this kind were taken from zoological authorities like textbooks or lectures. However, students used induction when in more familiar contexts. Moreover, when generalizations were analysed in the sense of Dewey, it became evident that students are fully capable of making generalizations by transferring meaning from one experience to another. The implications of these results for using induction and hypotheses testing in instruction are discussed.

TErritorial defence and mating success in males of the small heath butterfly, coenonympha pamphilus L. (Lepidoptera: Satyridae)

Abstract It has long been recognized that territorial defence in male butterflies must be some sort of mating strategy and that the territories are used as mating stations. However, so far, no systematic study has established the adaptive significance of territorial behaviour. This study is an attempt to fill this gap. By comparing the distribution of territories with the distribution of locations where wild and released virgin females mated this study shows that, in the small heath butterfly ( Coenonympha pamphilus ), males in territories have higher mating success than males outside territories. This supported the hypotheses that the function of territorial behaviour is to secure more matings and that the territories are mating stations. Wing length measurements suggest the same. Large males residing in territories tended to mate more often than small males, which were usually found outside territories. Since resident males were larger than non-resident males, this size difference was used to see how territorial occupancy influenced longevity. Mark-recapture of measured males revealed no significant correlation between wing length and the further life expectancy of males, strongly suggesting that the mating success of males in territories is also higher when measured over their whole lifetime.

A sex difference in the propensity to enter direct/diapause development: a result of selection for protandry

In monandrous mating systems with discrete nonoverlapping generations males should maximize the expected number of matings by starting to emerge before females. This is known as protandry. Moreover, Evolutionarily Stable Strategies (ESS) models show that the male emergence curve should be abruptly truncated before female emergence has ceased. In temperate areas where many insects have partial second generations, we accordingly predict that males should enter diapause development at an earlier date than should females, as a result of late‐emerging males being penalized in terms of fewer mating opportunities. The decision to diapause or to develop directly is usually mediated by response to environmental stimuli of which day length is the most important. Hence we predict that the mechanism by which males enter diapause at an earlier date than females will be that of the male reaction norm for diapause development being shifted towards longer day lengths when compared to that of females. As a result of the greater tendency of males to enter diapause development, partial second generations that develop directly should be female biased. As a corollary, first generations should be male biased because some males of the first generation are from the previous year. The prediction that males should enter diapause development earlier in the season, i.e., at longer day lengths, as compared to females was corroborated by rearing Pieris napi under a variety of critical day length regimes producing mixed broods of directly developing and diapausing individuals, and by outdoor rearings of cohorts of larvae of P. napi and P. rapae initiated throughout the season. The prediction that partial second generations should be female biased was corroborated by laboratory rearings at constant temperature of P. napi (Pieridae), Polygonia c‐album (Nymphalidae), and Pararge aegeria (Satyridae) under critical day length conditions, producing female‐biased sex ratio under direct, and male‐biased sex ratio under diapause development.

Science learning and epistemology

Learning theories presuppose views about knowledge. Different learning theories in science rely on, and draw from, various epistemological perspectives. In this chapter, we will examine the relationship between learning and epistemology in science education. We consider the ways that history, philosophy, and sociology of science have informed learning theory (disciplinary perspective), ways that students’ personal epistemologies influence learning (personal ways of knowing), and emerging studies of practical epistemologies that consider ways that disciplinary practices are enacted interactionally in learning contexts (social practices perspective). We consider how conceptions of knowledge are operationalized in science learning research across these perspectives and draw implications for research in science education.

Larval aestivation and direct development as alternative strategies in the speckled wood butterfly, Pararge aegeria, in Sweden

ABSTRACT. 1 Sweden has two disjunct populations of the speckled wood butterfly, Pararge aegeria L. The southern population has two generations per year but the central Swedish population is univoltine. When rearing larvae from central Sweden under normal photoperiodic conditions but at temperatures slightly above the ambient, 42% of the larvae developed directly and produced a second generation of adults the same summer. The egg—larval development time of the directly developing individuals was about 40 days, whereas that of the individuals developing along the univoltine pathway was about 100 days. 2 Larvae of the central Swedish population normally aestivate during part of the summer even though abundant food is available. In the closely related Lasiommata petropolitana F., which is the only Swedish satyrid that overwinters in the pupal stage besides P.aegeria, larvae do not aestivate, indicating that there does not seem to be any obligatory association between pupal hibernation and larval aestivation. 3 Development rates of aestivating and directly developing P.aegeria are equal up to the third larval instar. During the third and fourth instars, however, the development rate of aestivating individuals is retarded and females also have an additional fifth instar. 4 Since the central Swedish P.aegeria have the capacity to develop directly, and the southern Swedish ones have the capacity to aestivate, the evidence indicates that the outcome of the cost/benefit balance of univoltine versus bivoltine development differs between the two areas.

Teachers’ objects of responsibility – Something to care about in education for sustainable development?

Answers to questions about good teaching in environmental education can be expressed in different selective traditions. Questions as to what should be included in good teaching tend to be addressed by both teachers and researchers on an ideological basis. This qualitative study uses a pragmatist approach, and aims to make an empirical contribution to the debate. Rather than telling teachers what they should teach, this interview study involved listening to ten upper secondary school teachers in Sweden, and their arguments concerning their long‐term teaching purposes. Why should students learn particular things? The teachers’ answers revealed habits and frequently used the same arguments. These arguments recurrently dealt with what teachers particularly cared about, and five objects of responsibility were identified in the interviews. These objects of responsibility constitute the starting points of teachers’ actions and can be seen as personal anchor points within a selective tradition. These points of departure remind the teachers of their teaching aims and objectives, and at the same time, keep them within a tradition. While they help the teachers in their everyday practice, they could just as easily be seen as tacit obstacles to efforts to change environmental education into Education for Sustainable Development. The results are also relevant for science education in general. Issues identified in the study include how the same scientific knowledge could be used for different purposes in education, and the different personal anchor points for long‐term purposes of teaching based on teachers’ own ideas of good teaching. These results can be important in developing a reflection tool for teachers, which in turn can help them to reflect more deeply about how they might change their teaching practices.