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A Forficula auricularia L. (Dermaptera: Forficulidae), earwig insect, species-complex contact zone in the Pyrenees Mountains has been analyzed. Two sibling species differ in life history and have diverged at the molecular level. The PCR-RFLP method was used on two mitochondrial regions. Findings show coexistence of the sibling species at an intermediate altitude, but at lower and higher altitudes only one species was seen

The European earwig (Forficula auricularia) was formerly thought to present a mosaic of populations differing in their reproductive biology. We show that it is comprised of two as yet unrecognized sibling species. The molecular divergence between the two species, for a 627-bp amplified fragment overlapping the COI and COII mitochondrial loci, is six times larger than intraspecific variation. A species with two clutches a year lives predominantly in lowland and oceanic European habitats. A species with one clutch a year-except in the Mediterranean area where it has two clutches-lives predominantly in highland and continental European habitats. They both invaded North America during the 20th century, respectively, from the west and the east coasts, with no apparent mixing of their populations. The two species can occur in sympatry in Europe and are reproductively isolated by nearly complete failure to produce F 1 hybrids., (© 1998 The Society for the Study of Evolution.)

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.

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., (Copyright © 1992. Published by Elsevier B.V.)

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)., (Copyright © 1990. Published by Elsevier B.V.)

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).

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.