The validity of ecogeographical rules is context‐dependent: testing for Bergmann's and Allen's rules by latitude and elevation in a widespread Andean duck

Consistent responses by various organisms to common environmental pressures represent strong evidence of natural selection driving geographical variation. According to Bergmann's and Allen's rules, animals from colder habitats are larger and have smaller limbs than those from warmer habitats to minimize heat loss. Although evidence supporting both rules in different organisms exists, most studies have considered only elevational or latitudinal temperature gradients. We tested for the effects of temperature associated with both elevation and latitude on body and appendage size of torrent ducks (Merganetta armata), a widespread species in Andean rivers. We found a negative relationship between body size and temperature across latitude consistent with Bergmann's rule, whereas there was a positive relationship between these variables along replicate elevational gradients at different latitudes. Limb‐size variation did not support Allen's rule along latitude, nor along elevation. High‐elevation ducks were smaller and had longer wings than those inhabiting lower elevations within a river. We hypothesize that temperature is likely a major selective pressure acting on morphology across latitudes, although hypoxia or air density may be more important along elevational gradients. We conclude that the effect of temperature on morphology, and hence the likelihood of documenting ecogeographical ‘rules’, depends on the environmental context in which temperature variation is examined. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 850–862.     

Patterns of sexual size dimorphism in Chelonia: revisiting Kinosternidae

Rensch's rule, a macroevolutionary pattern in which sexual size dimorphism (SSD) increases with body size in male‐biased SSD species, or decreases with female‐biased SSD species, has been investigated in many vertebrates because it indicates whether SSD is being driven by sexual selection or a different force (i.e. fecundity or natural selection). Evidence in turtles has shown some conflicting results, which may be explained by the different phylogenies used in the analyses. Because the newly available well‐resolved phylogeny of family Kinosternidae provides evidence for the ancient monophyly of Staurotypidae and Kinosternidae and their recognition as separate families (previously Staurotypidae was considered as a subfamily within Kinosternidae) and introduced the genus Cryptochelys for the monophyletic leucostomum clade, we revisit the pattern of SSD and body size in Kinosternidae. By contrast to what had been proposed, we found that the Kinosternidae as formerly recognized (i.e. including Staurotypus and Claudius) and the restricted Kinosternidae both follow a pattern consistent with Rensch's rule. Our analysis with published body size data did not change our results, confirming the importance of the phylogeny used in macroevolutionary studies. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 806–809.     

Northern richness and cryptic refugia: phylogeography of the Italian smooth newt Lissotriton vulgaris meridionalis

Recent phylogeographical studies have re‐evaluated the role of refugia in central and northern Europe for glacial persistence and postglacial assembly of temperate biota. Yet, on a regional scale within Mediterranean peninsulas, putative ‘northern’ refugia's contribution to the current structure of biodiversity still needs to be fully appreciated. To this end, we investigated the phylogeographical structure and the evolutionary history of the Italian smooth newt, Lissotriton vulgaris meridionalis, through phylogeographical, molecular dating and historical demographic analyses. We found ten differentiated mitochondrial lineages with a clear geographical association, mainly distributed in northern Italy. The most ancient divergence among these lineages was estimated at the Early Pleistocene and was followed by a series of splits throughout the Middle Pleistocene. No haplogroup turned out to be derived from another one, each one occupying terminal positions within the phylogenetic network topologies. These results suggest an unprecedented scenario involving long‐term survival of distinct evolutionary lineages in multiple northern Mediterranean refugia. This scenario mirrors on a smaller geographical scale what has been previously observed in the literature concerning northern European environments; it also sheds more light on how northern Italy has contributed to temperate species' long‐term survival and to the assembly of regional biota. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 590–603.     

The influence of environmental factors on the morphology of red‐backed voles Myodes gapperi (Rodentia,Arvicolinae) in Québec and western Labrador

Geographical patterns of morphological variation in small mammals are often associated with environmental factors. The southern red‐backed vole Myodes gapperi is a widespread and abundant small mammal in Canada, occurring in environments as diverse as mixed‐wood forests and taiga. First upper molars and skulls from nine populations of southern red‐backed voles distributed across three ecozones and approximately 10° of latitude were analysed by means of geometric morphometric techniques, and their relationships with environmental variables were examined. A weak, non‐linear trend of size increase towards higher latitudes was observed in voles' skulls. Environmental variables appeared to be important drivers of shape differentiation among populations from the three distinct ecozones analysed. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 204–218.     

Darwin was right: inbreeding depression on male fertility in the Darwin family

Charles Darwin, who was married to his first cousin Emma Wedgwood, was the first experimentalist to demonstrate the adverse effects of inbreeding. He documented the deleterious consequences of self‐fertilization on progeny in numerous plant species, and this research led him to suspect that the health problems of his 10 children, who were very often ill, might have been a consequence of his marriage to his first cousin. Because Darwin's concerns regarding the consequences of cousin marriage on his children even nowadays are considered controversial, we analyzed the potential effects of inbreeding on fertility in 30 marriages of the Darwin–Wedgwood dynasty, including the marriages of Darwin's children, which correspond to the offspring of four cousin marriages and three marriages between unrelated individuals. Analysis of the number of children per woman through zero‐inflated regression models showed a significantly adverse effect of the husband inbreeding coefficient on family size. Furthermore, a statistically significant adverse effect of the husband inbreeding coefficient on reproductive period duration was also detected. To our knowledge, this is the first time that inbreeding depression on male fertility has been detected in humans. Because Darwin's sons had fewer children in comparison to non‐inbred men of the dynasty, our findings give empirical support to Darwin's concerns on the consequences of consanguineous marriage in his own progeny. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 474–483.     

Display behaviour and dewlap colour as predictors of contest success in brown anoles

Many animals display visual signals in male contests for access to females and territories. These visual signals can be multimodal and stimulate different aspects of a signal receiver's visual system. Over two summers, we tested whether aspects of behaviour and dewlap colour might function as signals that predict contest success when males compete for access to either mates or territories in male brown anole lizards. We found that behaviour (PC1, a correlated composite of head‐bob, push‐up, and dewlap extension frequency) and an aspect of dewlap colour (PC3, the relative amounts of ultraviolet, yellow, orange, and red of the dewlap margin) were retained in the minimum adequate model predicting contest success across years and social contexts. Winners showed significant differences in behaviour (winners displayed more) and dewlap margin PC3 (winners had lower PC3 scores) compared to contest losers. These findings suggest that display behaviour and dewlap colour might serve as signals indicating a male's ability to win contests for access to females and territories. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 646–655.     

Sexual selection,phenotypic variation,and allometry in genitalic and non‐genitalic traits in the sexually size‐dimorphic stick insect Micrarchus hystriculeus

The mobility hypothesis could explain the evolution of female‐biased size dimorphism if males with a smaller body size and longer legs have an advantage in scramble competition for mates. This hypothesis is tested by performing a selection analysis in the wild on Micrarchus hystriculeus (Westwood) (Phasmatodea), a sexually size dimorphic stick insect endemic to New Zealand. This analysis examined the form and strength of sexual selection on body size, leg lengths (front, mid and hind), and clasper size (a genitalic trait), and also quantified the degree of phenotypic variation and the allometric scaling pattern of these traits. By contrast to the mobility hypothesis, three lines of evidence were found to support significant stabilizing sexual selection on male hind leg length: a significant nonlinear selection gradient, negative static allometry, and a low degree of phenotypic variation. Hind leg length might be under stabilizing selection in males if having average‐sized legs facilitates female mounting or improves a male's ability to achieve the appropriate copulation position. As predicted, a negative allometric scaling pattern and low phenotypic variation of clasper size is suggestive of stabilizing selection and supports the ‘one‐size‐fits‐all’ hypothesis. Opposite to males, the mid and hind leg lengths of females showed positive static allometry. Relatively longer mid and hind leg lengths in larger females might benefit individuals via the better support of their larger abdomens. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 471–484.     

Does ‘gliding while gravid’ explain Rensch's rule in flying lizards?

Among species with sexual size dimorphism (SSD), taxa in which males are the larger sex have increasing SSD with increasing body size, whereas in taxa in which females are the larger sex, SSD decreases with body size: Rensch's rule. We show in flying lizards, a clade of mostly female‐larger species, that SSD increases with body size, a pattern similar to that in clades with male‐biased SSD or more evenly mixed SSD. The observed pattern in Draco appears due to SSD increasing with evolutionary changes in male body size; specifically divergence in body size among species that are in sympatric congeneric assemblages. We suggest that increasing body size, resulting in decreased gliding performance, reduces the relative gliding cost of gravidity in females, and switches sexual selection in males away from a small‐male, gliding advantage and toward selection on large size and fighting ability as seen in many other lizards. Thus, selection for large females is likely greater than selection for large males at the smaller end of the body size continuum, whereas this relationship reverses for species at the larger end of the continuum. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 270–282.     

The influence of tectonics,sea‐level changes and dispersal on migration and diversification of Isonandreae (Sapotaceae)

Internal transcribed spacer (ITS) ribosomal DNA sequence data were generated for 80 of the c. 200 species of Isonandreae and were added to data from African and Neotropical representatives in subfamily Sapotoideae and outgroups in Sapotaceae. Bayesian dating and ancestral area reconstruction indicated that Isonandreae are derived from within an African grade. Multiple Australasian species or lineages are derived from Sundanian lineages in South‐East Asia with stem ages originating from the late Oligocene. Sri Lankan and Indian lineages are also derived from Sundanian lineages. Our results are consistent with migration from Africa into Sundania followed by numerous over‐water dispersal events across Wallace's Line into Australasia and migration from Sundania to the Indian subcontinent. Pleistocene speciation indicates that sea‐level changes during that epoch could have been responsible for some species diversification in Sundania. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 130–140.     

Type designation of the oaks Quercus ballota and Q. rotundifolia (Fagaceae)

The names Quercus ballota and Q. rotundifolia (Fagaceae), referring to taxa sometimes considered conspecific with the widely distributed Q. ilex, are discussed and typified. A specimen preserved at MPU is designated as the lectotype of Desfontaines's name Q. ballota. Lamarck's name Q. rotundifolia is neotypified using a specimen preserved at VAL, with several duplicates in other European herbaria.     

Re‐contemplate an entangled bank: The Power of Movement in Plants revisited

We review the ways in which two of Charles Darwin's lesser known works, The Movement and Habit of Twining Plants and The Power of Movement in Plants, stimulated 20th and 21st century research findings and philosophies. The legacy of Darwin's work permeates research on plant movement. For example, Darwin's demonstration that coleoptiles and roots fail to bend in response to light or gravity if their tips are removed helped researchers work toward the discovery of auxin and other plant hormones. Darwin's methodical observations on vine twining directions and circumnutation foreshadowed the recent discovery that 92% of vines twine in right‐handed helices, regardless of their location on the planet. Finally, Darwin's observation of the similarity between plant responses to stimuli and the responses of lower animals foreshadowed the current debate over whether plants have ‘behaviour’. Thus, even Darwin's lesser‐known works continue to influence research in the present day. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 111–118.     

Genome size evolution in Sapindaceae at subfamily level: a case study of independence in relation to karyological and palynological traits

Sapindaceae s.l. is a moderately large family of trees, shrubs and lianas. Current knowledge on genome size and how it varies in this family is scarce. This research aims to characterize the DNA content in 39 species of Sapindaceae, mainly in tribe Paullinieae s.s., by the analysis of the variation in genome size relative to karyotypic and palynological features. Nuclear DNA amount was measured by flow cytometry, and linear regression analyses were conducted to analyse the relationship between genome size variation and various karyotypic and palynological features. Genome size varied nine‐fold among species, ranging from 1C = 0.305 pg (Lophostigma plumosum) to 2.710 pg (Cardiospermum heringeri). The low regression coefficients obtained suggest that genome size mainly varies independently of karyotypic and palynological features. With regard to karyotype evolution, the constant chromosome number but variable genome size in Houssayanthus, Paullinia and Serjania suggest that structural changes mainly caused by changes in the amounts of repetitive DNA are more important than numerical change. In contrast, in Cardiospermum and Urvillea, variation in chromosome number and genome size supports the suggestion that numerical and structural changes are important in the karyotype evolution of these genera. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 589–600.     

Patrick Matthew's law of natural selection

Patrick Matthew is the little‐known first originator of macroevolution by natural selection. I review his ideas, and introduce some previously unnoticed writings (catalogued at a new website: http://smarturl.it/patrickmatthew ) that clarify how they differ from Darwin's and Wallace's. Matthew's formulation emphasized natural selection as an axiomatic ‘law’ rather than a ‘theory’, a distinction that could still be of use to us today. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●● , ●●–●●.     

Multiple paternity in the starry smooth‐hound shark Mustelus asterias (Carcharhiniformes: Triakidae)

Multiple paternity was investigated in the starry smooth‐hound shark, Mustelus asterias Cloquet, 1821. Analysis of 12 pregnant females and their embryos, at four microsatellite loci, showed that at least 58% carried multiply‐sired litters. Paternal skew was observed, with one male siring most of the embryos within a litter, although no patterns of association were detected between the identity of the father and the size or the uterine position of the embryos. Sperm storage was observed in the oviducal glands of all twelve females. Results shed light on the complexity of reproductive strategies and selective processes in M. asterias. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 119–125.     

Under pressure: morphological and ecological correlates of bite force in the rock‐dwelling lizards Ouroborus cataphractus and Karusasaurus polyzonus (Squamata: Cordylidae)

Rock‐dwelling lizards are hypothesized to be highly constrained in the evolution of head morphology and, consequently, bite force. Because the ability to generate a high bite force might be advantageous for a species' dietary ecology, morphological changes in head configuration that allow individuals to maintain or improve their bite force under the constraint of crevice‐dwelling behaviour are to be expected. The present study addressed this issue by examining head morphology, bite force, and a number of dietary traits in the rock‐dwelling cordylid lizards Ouroborus cataphractus and Karusasaurus polyzonus. The results obtained show that O. cataphractus has a larger head and higher bite force than K. polyzonus. In K. polyzonus, head width, lower jaw length, and jaw closing‐in lever are the best predictors of bite force, whereas head height is the main determinant of bite force in O. cataphractus. Although the observed difference in bite force between the species does not appear to be related to dietary patterns or prey handling, the prey spectrum available for intake was greater in O. cataphractus compared to K. polyzonus. We discuss the influence of interspecific differences in anti‐predator morphology on head morphology and bite force in these rock‐dwelling species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 823–833.     

Do Micrognathozoa have micro‐genomes?

Based on the extremely small sizes of their jaw components, I predict that members of the Micrognathozoa will have some of the smallest nuclear genomes of any metazoans or, possibly, even of any free‐living (non‐parasitic) eukaryotes. Micrognathozoan jaws may also be enervated by anucleate neurons. Consistent with the prediction of small genomes, micrognathozoan jaw parts have remarkably small cell nuclei. Identical arguments may apply to other members of the Gnathifera, namely Rotifera and Gnathostomulida. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 640–644.     

Parental defence on the reef: antipredator tactics of coral‐reef fishes against egg‐eating seasnakes

On coral reefs in New Caledonia, the eggs of demersal‐spawning fishes are consumed by turtle‐headed seasnakes (Emydocephalus annulatus). Fish repel nest‐raiding snakes by a series of tactics. We recorded 232 cases (involving 22 fish species) of antipredator behaviour towards snakes on a reef near Noumea. Blennies and gobies focused their attacks on snakes entering their nests, whereas damselfish (Pomacentridae) attacked passing snakes, as well as nest‐raiders (reflecting territorial defence). Biting the snake was the most common form of attack, although damselfish and blennies also slapped snakes with the tail, or (blennies only) plugged the nest entrance with the parent fish's body. Gobies rarely defended the nest, although they sometimes bit or threw sand at the snake. A snake was more likely to flee if it was attacked before it began feeding rather than after it found the eggs (82% versus 3% repelled) and if bitten on the head rather than the body (68% versus 53%). Tail‐slaps were not effective, although plugging the burrow and throwing sand often caused snakes to flee. These strong patterns reflect phylogenetic variation in fish behaviour (e.g. damselfish detect a snake approach sooner than do substrate‐dwelling blennies and gobies) coupled with intraspecific variation in snake diets. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 415–425.