Construction of Selection Indexes with Restrictions

In this paper the problem of unistage selection with inequality constraints is formulated. If the predictor and criterion variables are all normally distributed, this problem can be written as a convex programming problem, with a linear objective function and with linear constraints and a quadratic constraint. Using the duality theory, for convex nonlinear programming it is proved, that its dual problem can be transformed into a convex minimization problem with non-negativity conditions. Good computational methods are known for solving this problem. By the help of the dual problem sufficient conditions for a solution of the original primal problem are derived and illustrated by an example of practical interest.     

A cladistic and comparative analysis of kinematic components of the fast-start of fishes,with a note on body size constraints

The fast-start is an ecologically relevant behavior pattern in fishes. The present article analyses the distribution of five continuous kinematic traits (latency for response initiation, time to maximum angular velocity, time to maximum displacement velocity, maximum angular velocity, and maximum displacement velocity) in eight of the eleven species described in Eaton (66:65–81, 1977). Phylogenetic generalized least square estimation of ancestor states demonstrated evolutionary changes in maximum angular velocity and maximum displacement velocity, consistent with species differences in the same variables. These changes in maximum velocity are also correlated (phylogenetically independent contrasts) with the mean body sizes of all species, pointing to the possibility that body size was an evolutionary constraint on maximum velocities. The conservation of the other traits suggest that they are mainly constrained by neural control, and a trade-off between neural and body size-constraints is proposed ex hypothesi. An erratum to this article can be found at     

Dispersal ability rather than ecological tolerance drives differences in range size between lentic and lotic water beetles (Coleoptera: Hydrophilidae)

Aim In aquatic ecosystems, standing (lentic) and running (lotic) waters differ fundamentally in their stability and persistence, shaping the comparative population genetic structure, geographical range size and speciation rates of lentic versus lotic lineages. While the drivers of this pattern remain incompletely understood, the suite of traits making up the ability of a species to establish new populations is instrumental in determining such differences. Here we explore the degree to which the association between habitat type and geographical range size results from differences in dispersal ability or fundamental niche breadth in the members of the Enochrus bicolor complex, an aquatic beetle clade with species across the lentic–lotic divide. Location Western Mediterranean, with a special focus on North Africa, the Iberian Peninsula and Sicily. Methods DNA sequences for four loci were obtained from species of the E. bicolor complex and analysed using phylogenetic inference. Dispersal and establishment abilities were assessed in lentic–lotic species pairs of the complex, using flight wing morphometrics and thermal tolerance ranges as surrogates, respectively. Results There were clear differences in range size between the lotic and lentic taxa of the complex, which appears to have had a lotic origin with two transitions to standing waters. Only small differences were observed in temperature tolerance and acclimation ability between the two lotic–lentic sister species studied. By contrast, wing morphometrics revealed clear, consistent differences between lotic and lentic Enochrus species pairs, the latter having a higher dispersal capacity. Main conclusions We hypothesize that there have been two habitat shifts from lotic to lentic waters, which have allowed marked expansions in geographical range size in western Mediterranean species of the E. bicolor complex. Differences in dispersal rather than in establishment ability appear to underlie differences in geographical range extent, as transitions to lentic waters were associated with changes in wing morphology, but not in thermal tolerance range. In this lineage of water beetles, selection for dispersal in geologically short‐lived lentic systems has driven the evolution of larger range sizes in lentic taxa compared with those of their lotic relatives.     

The influence of host distribution, sex, and size on the level of parasitism by Itoplectis conquisitor (Hymenoptera: Ichneumonidae)

Abstract. 1. Parasitism of the bagworm, Thyridopteryx ephemeraeformis Haw. (Lepidoptera: Psychidae), on red cedar was studied at Manassas, Va., U.S.A.
2. Fifteen parasitoids, five of which were hyperparasitoids, attacked the pupal stage of the bagworm. The Ichneumonid Itoplectis conquisitor alone accounted for 58% of the parasitized bagworms.
3. Parasitism by I conquisitor (Say) was inversely related to host size, but independent of host distribution within a tree. Male bagworms experienced disproportionately higher levels of parasitism than females. We conclude that it is small size that renders bagworms susceptible to parasitism rather than sex per se.
4. Ovipositor lengths of I.conquisitor were insufficient to penetrate the larger bagworm hosts (>57 mm); and in fact, as bagworm size increased, the proportion of the I.conquisitor population capable of penetrating the pupa declined abruptly. We suggest that the mechanical difficulties with oviposition, and perhaps the defensive capabilities of larger hosts, are responsible for the relationship between host size and per cent parasitism.
5. I.conquisitor could be an important selective agent for bagworm size at pupation, but it is not likely to act as a significant control agent of population density.     

Acquérir l’ivoire vrai et lui donner forme : contraintes pratiques et techniques

Dealing with objects made on osseous materials as mammoth ivory involves questions about the availability of this raw material within the territories occupied by palaeolithic societies. In the case of green ivory procurement, this availability is directly linked with the geographical distribution of mammoth populations. The ways of procurement of this raw material seem to be guided also by some cultural traditions. The authors propose a reflexion about these zooarchaeological issues and the first technical gestures, which come in the initial stages of any exploitation of true ivory.     

A null model for species richness gradients: bounded range overlap of butterflies and other rainforest endemics in Madagascar

Species richness has classically been thought to increase from the poles towards the Equator, and from high elevations down to sea-level. However, the largest radiation of butterflies in Madagascar, the subtribe Mycalesina (c. 67 spp.) does not exhibit such a monotonic pattern, either for empirical records or for interpolated species ranges. Instead, summation of mycalesine ranges generates a domed curve of species richness values approximately symmetric around mid latitudes within the island, a pattern most smoothly exhibited by the wider ranging and better known species, and a less symmetric curve peaking near mid elevations. Hotspots for the summation of 1183 species ranges and seven out of the ten groups of insects and vertebrates analysed (butterflies, cicindelid and enariine melonthid beeties, ctenuchiine moths, chameleons, frogs, birds, lemurs, tenrecs, and rodents) also occur at both mid latitudes and elevations. The most strongly parabolic pattern is shown by animals (637 spp.) whose ranges are confined to the highly linear rainforest biome. This rainforest species richness curve is resilient in shape even after controlling for particular effects of area and irregular sample effort. In sharp contrast, at least eight different environmental parameters for the rainforest biome tend to increase monotonically towards the northern, more tropical, boundary, a trend evident only in species richness gradients of more narrow-ranging species. The one-dimensional latitudinal species richness curves and hotspots observed in fact best reflect overall the geometric predictions of a null model for ranked range size partitions of the regional species pool. This analytical model is based on the uniform probability distribution, and assumes that species ranges are constrained by the position of biome or island boundaries. The same logarithmic equations applied iteratively to longitude also accurately predict hotspots for more realistic species ranges containing gaps, as shown for two-dimensional species richness patterns for the Madagascan rainforest dataset. Bio-geographic and conservation implications of the bounded range overlap concept are discussed.     

Cooperative breeding in birds: the role of ecology

Theory predicts that cooperative breeding should only occurin species in which certain individuals are constrained frombreeding independently by some peculiarity of the species' ecology.Here, we use comparative methods to examine the role of variationin ecology in explaining differences between taxa in the frequencyof cooperative breeding. We address three questions. First,does the frequency of cooperative breeding vary at just one phylogeneticlevel, or across several levels? Second, are differences inthe frequency of cooperative breeding among closely-relatedspecies correlated with ecology? Last, are ecological differencesbetween ancient lineages important in predisposing certain lineagesto cooperative breeding? We find that variation in the frequencyof cooperative breeding occurs across all phylogenetic levels,with 40% among families and 60% within families. Also, variationin the frequency of cooperative breeding between closely related speciesis associated with ecological differences. However, differencesin the frequency of cooperative breeding among more ancientlineages are not correlated with differences in ecology. Together,our results suggest that cooperative breeding is not due toany single factor, but is a two step-process: life-history predispositionand ecological facilitation. Low annual mortality predisposescertain lineages to cooperative breeding. Subsequently, changesin ecology facilitate the evolution of cooperative breedingwithin these predisposed lineages. The key ecological changesappear to be sedentariness and living in a relatively invariableand warm climate. Thus, although ecological variation is notthe most important factor in predisposing lineages to cooperativebreeding, it is important in determining exactly which speciesor populations in a predisposed lineage will adopt cooperativebreeding.     

Hydrophobic forces are responsible for the folding of a highly potent natriuretic peptide analogue at a membrane mimetic surface: An NMR study

A conformational study by nmr spectroscopy was performed with the highly active 28-residue hybrid natriuretic peptide analogue pBNP1 [M. Mimeault, A. De Léan, M. Lafleur, D. Bonenfant, and A. Fournier (1995) Biochemistry, Vol. 34, pp. 955–964], which consists of the cyclic peptide core of pBNP32 and the N- and C-terminal exocyclic segments of rANP(99–126). In purely aqueous solution pBNP1 exhibits random coil behavior as evidenced by the almost complete absence of structurally significant nmr observables. By contrast, elements of secondary structure emerged upon the addition of dodecylphosphocholine micelles to the aqueous sample. Nuclear Overhauser effect distance-restrained molecular dynamics simulations in conjunction with torsional angle determinations permitted the generation of a reasonable model of the lipid-bound conformation of pBNP1. According to this model, pBNP1 adopts turn-like features in the cyclic and C-terminal regions of the peptide, but remains quite flexible in the N-terminal segment. Two hydrophobic cores separated by a hydrophilic cleft were also evident in the generated structure. A mechanism is proposed whereby the hydrophobic interactions necessary to stabilize a folded structure of pBNP1 are facilitated by the presence of the membrane-like polar/apolar interface provided by the phospholipid micelles. © 1997 John Wiley & Sons, Biopoly 42: 37–48, 1997     

Life span variation in 13 Drosophila species: a comparative study on life span,environmental variables and stress resistance

Recently, heterogeneity of the environment has been suggested as an important player in the evolution of life span variation. Established ageing theories propose that life span variation is the result of coevolution with other traits, such as stress resistance. This study aimed to compare these alternative hypotheses by examining the relationship between four environmental variables and different types of stress resistance traits with life span in 13 Drosophila species originating from tropical, subtropical and temperate environments (ecotypes). Average life span was found to differ significantly both between species and sexes, but only male life span correlated with the environment and cold resistance. While controlling for phylogeny, the environmental variable precipitation seasonality and resistance against cold‐induced stress explained most variation in male life span. Furthermore, male life span varied between species in a manner represented by environmental variables linked to the different ecotypes, such that tropical species lived longer and were less cold resistant. The current results suggest that general mechanisms underlying stress resistance and life span are unlikely. In addition, our results point to the environment independently shaping variation in life span and cold resistance rather than genetic interactions.