Pierre Deleporte

Phylogenetics and Ecology: As Many Characters as Possible Should Be Included in the Cladistic Analysis☆

As many data as possible must be included in any scientific analysis, provided that they follow the logical principles on which this analysis is based. Phylogenetic analysis is based on the basic principle of evolution, i.e., descent with modification. Consequently, ecological characters or any other nontraditional characters must be included in phylogenetic analyses, provided that they can plausibly be postulated heritable. The claim of Zrzavý (1997, Oikos 80, 186–192) or Luckow and Bruneau (1997, Cladistics 13, 145–151) that any character of interest should be included in the analysis is thus inaccurate. Many characters, broadly defined or extrinsic (such as distribution areas), cannot be considered as actually heritable. It is argued that we should better care for the precise definition and properties of characters of interest than decide a priori to include them in any case in the analysis. The symmetrical claim of de Queiroz (1996, Am. Nat. 148, 700–708) that some characters of interest should better be excluded from analyses to reconstruct their history is similarly inaccurate. If they match the logical principles of phylogenetic analysis, there is no acceptable reason to exclude them. The different statistical testing strategies of Zrzavý (1997) and de Queiroz (1996) aimed at justifying inclusion versus exclusion of characters are ill‐conceived, leading respectively to Type II and Type I errors. It is argued that phylogenetic analyses should not be constrained by testing strategies that are downstream of the logical principles of phylogenetics. Excluding characters and mapping them on an independent phylogeny produces a particular and suboptimal kind of secondary homology, the use of which can be justified only for preliminary studies dealing with broadly defined characters.

Charles Darwin, earthworms and the natural sciences: various lessons from past to future

Abstract In 1881, Darwin (1809–1882) published his last scientific book entitled “The formation of vegetable mould through the action of worms with observations on their habits”, the result of several decades of detailed observations and measurements on earthworms and the natural sciences. The work was considered a “best-seller” at the time, with 3500 copies sold immediately and 8500 in less than 3 years which, at the time, rivaled the sale of his most well known book “On the origin of species”. The book covers the importance of earthworm activity on a variety of topics: pedogenesis and weathering processes, soil horizon differentiation and the formation of vegetable mould (topsoil), the role of earthworm burrowing and casting (bioturbation) in soil fertility and plant growth, the burial of organic materials and soil enrichment with mineral elements, the global cycle of erosion–sedimentation with hydrologic and aerial transfers of fine particles brought up to the soil surface by earthworms and the protection of archaeological remains through their burial. Finally, Darwin also performed a series of original experiments to determine if earthworms possessed, or not, a certain “intelligence”. This part of the book was, among others, one of the main reasons for its success. In this article we analyze the success (past and present) of this book, Darwin’s own opinion of his book and the general contents of the work. Throughout, we discuss the main lessons to be learned from his ‘little’ (as he called it) book and provide brief historic reviews of major literary works on earthworms, both contemporary and posterior to Darwin, emphasizing his role as precursor and/or founder of various scientific disciplines (ethology, soil ecology and pedology). However, despite Darwin’s clear demonstrations of the importance of biological activities (earthworms) in the maintenance of soil fertility, his book on worms has been mostly neglected by agronomists and soil scientists, primarily due to the predominant soil fertility and management paradigms of the 19th and 20th centuries.

THE ORIGIN OF PROTISTAN SYMBIONTS IN TERMITES AND COCKROACHES: A PHYLOGENETIC PERSPECTIVE

Abstract— The controversy over whether protist symbionts ofCryptocercusand termites were inherited from a common ancestor or transferred secondarily has been long standing. We present here the first phylogenetic test of these hypotheses and show that the transfer hypothesis is better supported.

The phylogeny and behaviour of Cervidae (Ruminantia Pecora)

The phylogenetic relationships of Cervidae within the family and within the infra-order Pecora are still uncertain. Traditionally based on morphological data, phylogenetic trees have increasingly relied on molecular data for the last 15 years, without reaching a satisfying consensus solution. This study intends to explore behaviour, between the rutting and nursing periods, as a new data set for the establishment of phylogenetic relationships between the several species of Cervidae, and also between Cervidae and other living Pecora families (Antilocapridae, Bovidae, Giraffidae and Moschidae). Separate analysis of behavioural data was performed, followed by combined analysis of behavioural characters together with morphological and cytological ones. Simultaneous analysis of all characters showed that Cervidae form a monophyletic group made up of two lineages: plesiometacarpalians or Cervinae (Muntiacus (Dama, Cervus)), and telemetacarpalian cervids including Hydropotinae and Capreolinae (Hydropotes (Capreolus (Alces (Odocoileus, Rangifer)))). Moschidae appear as the sister group of Cervidae, and Bovidae seem more closely related to Cervoidea than are Giraffidae. An Eurasiatic origin for Cervidae is suggested. Our results also indicate that Hydropotes is secondarily antlerless. Ancestral ethotypes were reconstructed for several clades. On the basis of this case study, the relevance of behavioural characters for phylogenetic systematics is discussed.

Behaviours promoting grouping or dispersal of mother and neonates in ovoviviparous cockroaches

Summary. The nature of early relationships between mother and nymphs and among siblings was compared in four cockroach species belonging to the same ovoviviparous family (Zetoborinae) in order to characterise the behavioural interactions favouring dispersal or maintenance of the group of neonates. Behavioural interactions between mothers and their new-born nymphs and between two sibling neonates were video recorded and analysed with flow charts on factorial maps. In the solitary species Thanatophyllum akinetum, nymphs dispersed a few hours after birth without aggressiveness between siblings or between mother and offspring. In contrast females of Schultesia lampyridiformis displayed a behaviour never previously observed in cockroaches: aggression towards their own neonate nymphs, which could contribute to their dispersal. In Phortioeca nimbata and Lanxoblatta emarginata, nymphs stayed with their mother for 10 days, but social interactions differed between the two sp ecies: P. nimbata mothers actively searched for their nymphs, this behaviour being favoured by an active search for mutual contact by the nymphs themselves, while L. emarginata nymphs sought more actively the proximity of their mother but less contact between themselves. Thus, different species of Zetoborinae presented two types of dispersal of the young and two types of maintenance of the birth group, both achieved by specific behavioural interactions. The relevance of behavioural interactions for the characterisation of early gregarism and parental care is discussed.

Comparison of gregariousness in larvae and adults of four species of zetoborine cockroaches

Insects observed in groups in nature may be gathered either by attractants from the environment or by conspecifics. Field distribution data alone are thus insufficient to assess congregation by conspecifics and complementary laboratory tests of spacing patterns are required. Such tests were performed in four species of Zetoborinae (Insecta, Blattaria), for which field studies showed differences in spatial distribution (Schultesia lampyridiformis Roth, Phortioeca nimbata Burmeister, Lanxoblatta emarginata Burmeister and Thanatophyllum akinetum Grandcolas). Gregariousness, mobility, and sticking to shelters were compared between these four species. Tests were performed on pairs of adults of the same sex and opposite sexes, and also on first instar larvae, either in isolation or in groups of two and four individuals. In S. lampyridiformis, adults were strongly gregarious, whereas larvae dispersed early after birth and were very mobile during the first instar. In P. nimbata, larvae and adults were gregarious, while in L. emarginata larvae were weakly gregarious, and gregariousness decreased when density increased. Adults of L. emarginata seemed to be indifferent to each other. Larvae and adults of T. akinetum were solitary and they actively dispersed. The varying levels of gregariousness among species are discussed according to the known ecological habits in Zetoborinae.

Geometric morphometrics as a tool for improving the comparative study of behavioural postures

Describing postures has always been a central concern when studying behaviour. However, attempts to compare postures objectively at phylogenetical, populational, inter- or intra-individual levels generally either rely upon a few key elements or remain highly subjective. Here, we propose a novel approach, based on well-established geometric morphometrics, to describe and to analyse postures globally (i.e. considering the animal’s body posture in its entirety rather than focusing only on a few salient elements, such as head or tail position). Geometric morphometrics is concerned with describing and comparing variation and changes in the form (size and shape) of organisms using the coordinates of a series of homologous landmarks (i.e. positioned in relation to skeletal or muscular cues that are the same for different species for every variety of form and function and that have derived from a common ancestor, i.e. they have a common evolutionary ancestry, e.g. neck, wings, flipper/hand). We applied this approach to horses, using global postures (1) to characterise behaviours that correspond to different arousal levels, (2) to test potential impact of environmental changes on postures. Our application of geometric morphometrics to horse postures showed that this method can be used to characterise behavioural categories, to evaluate the impact of environmental factors (here human actions) and to compare individuals and groups. Beyond its application to horses, this promising approach could be applied to all questions involving the analysis of postures (evolution of displays, expression of emotions, stress and welfare, behavioural repertoires…) and could lead to a whole new line of research.

Biogeographic Analysis of Central African Forest Guenons

We analyzed biogeographic patterns of central African forest primates using a large locality sampling. Parsimony analyses of endemicity were performed simultaneously and separately on guenons and other primate fauna, on all localities and taxa, or by applying geographical and ecological filters. Results allow a reassessment of the delineation of forest faunal regions. Classic faunal regions are supported by this new and independent analysis, notably South Congo and East Congo. However, the West Central region reveals an unsuspected complexity, with two subunits South Ogooue and West Congo mixed with an otherwise largely unresolved intergradation zone.

THREE-TAXON STATEMENTS AND PHYLOGENY CONSTRUCTION

Abstract — The differences between the three‐taxon statement analysis and the standard approach are in the way they explicitly or implicitly consider character homology and modes of character evolution. The differences in the two methods have implications relative to the general model of evolution viewed as descent with modification of characters.

Social interactions during development in the ovoviviparous cockroach Schultesia lampyridiformis

Cockroaches are generally divided into solitary and gregarious species. Schultesia lampyridiformis (Zetoborinae) is a neotropical cockroach presenting unusual characteristics: it inhabits only pendulous nests of colonial Cacicus birds and feeds on broken eggs or bird corpses. This patchy habitat and food resource was expected to favour gregarious habits, which were effectively observed in adults. However, young nymphs dispersed during the first hours following birth. The gregarious life style should thus appear during the course of nymphal development. This study is aimed at specifying the timing of apparition of gregariousness during the development, and identifying the behaviours characterising the solitary and gregarious phases. We compared under experimental conditions social interactions and spatial distribution in pairs of nymphs at different instars (1, 2, 3, 5 and last instar) and in pairs of adult females. The gregarious phase appeared progressively in the last nymphal instars, and was characterized by a simultaneous increase in several behavioural features: length of interaction sequences, proportion of mutual antennal contacts, rate of answer to social stimulations from conspecifics and proportion of time spent close to conspecifics. This behavioural change is discussed regarding its possible function and importance for comparative studies of gregariousness.