Analysis of a contact zone in the Forficula auricularia L. (Dermaptera: Forficulidae) species complex in the Pyrenean Mountains.

The taxon Forficula auricularia L. (Dermaptera: Forficulidae) is a complex of two sibling species that differ in life history (number of clutches per year and imaginal diapause) and that have diverged at the molecular level. The study of a contact zone in the Pyrenean Mountains, using the PCR-RFLP method on two mitochondrial regions (the 16S rRNA and the Cytochrome Oxidase intergenic region), revealed the coexistence of the sibling species at intermediate altitude (1200 m) whereas at lower and higher altitudes only one species was found. An allozyme study, conducted simultaneously and based on four polymorphic loci (PGI1, AAT1, Est-P1 and Est-P2), showed no sign of nuclear introgression. The apparent lack of hybridization in the field is consistent with a postzygotic barrier observed in the laboratory (a nearly complete failure to produce F(1) hybrids). This contact zone is probably a sympatric zone between two genetically differentiated species.

Perception and learning in evolution.

Different theoretical models and methods exist which help to tackle the question of perception and learning in evolution. Waddington's genetic assimilation and its counterpart, the 'Wright Effect', provide a good methodological framework for experiments and simulations. Comparative analysis, in which phylogenetic as well as ecological aspects are considered, is another useful tool. These approaches consider cognitive processes with their simultaneous involvement in selective processes; they say very little about their emergence.

Introducing anthropomorphism, discontinuities and anecdotes to question them.

Recourse to anthropomorphism, folk psychology, or discontinuist thought, in order to take into account the richness of animal cognitive processes and of their evolution, is of some heuristic value. However, in the absence of recognised criteria allowing the hypothesised behavioural discontinuities between species to be tested and alternative interpretations of anecdotal reports to be selected, there is considerable risk that these alternatives will be ideological rather than scientific. A 'clinical analysis' of this anthropomorphism and discontinuist 'symptom' allows us to unravel its ideological aspect, namely the wishful thinking and the 'egomorphism' of a subject projecting a wishful representation of himself onto one who is not ego, and in turn to investigate its heuristic value in ethnological, psychopathological or animal behavioural studies. This analysis leads us to propose some tools:

Spread of phenotypic plasticity or genetic assimilation: the possible role of genetic constraints.

This paper considers possible outcomes of evolution in sexual diploid populations subjected to frequency-independent selection in favour of a phenotype which has appeared as a consequence of a change in environmental conditions. Depending on the details of genetic determination for the different development strategies ("plastic" or "canalized"), this situation results at least in either (i) the invasion of the population by "plastic" strategists, whose developmental plasticity was revealed by the environmental change, or (ii) the genetic assimilation of the new phenotype, or (iii) intermediate states in which only a certain proportion of individuals is genetically assimilated at equilibrium. Spread of plasticity during evolution in a series of distinct environments might, therefore, be hindered by genetic constraints.

Theoretical possibility of a genetic assimilation of the feeeing direction in Talitrus saltator.

Reports on the genetic assimilation of features involving behaviour are very scarce, while they are more common in the fields of morphology and physiology. This paper investigates the theoretical possibility of a genetic assimilation of the 'fleeing direction' in the sandhopper (Talitrus saltator), consistent with Bateson's model of genetic assimilation. This is done from the two simple genetic determinations suggested by L. Pardi and F. Scapini to explain the variability of the feature between populations. The conditions for this genetic assimilation to occur are examined and particular attention is paid to the differences between the properties of the two determinations. Finally, the possible importance of genetic assimilation in the field of animal orientation is discussed.

Behavioural development and adaptation: an assimilation of some of Waddington's ideas?

The paper discusses how ontogeny may contribute to the evolutionary processes dependent upon natural selection, as well as some of the answers that have been given to this essential question. The problem is addressed in relation to "instinctive" behaviour (maternal care) and to its evolutionary modification. The paper more particularly presents Waddington's contribution and the usefulness of his concept of "genetic assimilation". The conditions under which a specific adaptation might have evolved in the course of such a natural selective process are discussed. Finally, the constant reference to an epigenetic conception of phenotype (behaviour included) appears to be the Waddington's main contribution to evolutionary biology (ethology included).

Normal and experimentally induced changes in hormonal hemolymph titers during parental behavior of the earwig Labidura riparia.

The reproductive cycle of Labidura riparia includes two distinct phases of behavior: a feeding and sexual phase followed by a parental and fasting phase. These phases correspond to two contrasting physiological phases (vitellogenesis, followed by ovarian inactivity). These correlations have been verified by correlating radioimmunoassay (RIA) measurements of the levels of circulating juvenile hormones (JH) and ecdysteroids with ovarian state during the first reproductive cycle. Similar studies were also made after experimentally suppressing parental activity (care of eggs) either by depriving females of their eggs or by force-feeding during the egg-care phase. Taking eggs away without feeding caused the disappearance of parental behavior and a short lived period of vitellogenesis. Likewise, feeding in the presence of eggs resulted in vitellogenesis and disappearance of egg-care behavior. Thus, it appears that in order for the parental phase to develop normally it is necessary to preserve the proper external conditions (the presence of eggs) and physiological conditions (fasting).

[Parental behavior in Dermaptera]. / Le comportement parental des Dermaptères.

Parent-young relations are far from being unvarying and simple, even within a group as homogeneous and modest in number (1000 actual species) as Dermaptera. Care of the eggs by a female and the contacts she maintains with her larvae are neither established nor developed in an automatic way, but are amenable to important regulations in which behaviour itself is implied. The presence of larvae also has an important effect on the later development of the female's behaviour. Relationships can be established between known inter and intraspecific differences and between. -- the ovarian organization and activity of each species or population, on the one hand and -- the living conditions adopted by each species or population (Labidura riparia, Anechura bipunctata, Forficula auricularia) on the other. Collecting all the eco-etho and physiological data can be useful for understanding the development of Dermapteran maternal behaviour.