Romain Boisseau

University of Lausanne | UNIL · Department of Ecology and Evolution

Sexual cannibalism is often set apart from other forms of cannibalism; however, no studies have directly compared the fitness consequences of these 2 types of cannibalism. Here, we compared the consequences of cannibalism of a male by a female outside the context of mating (referred to as nonsexual cannibalism) and within the context of mating (ref...

Characterizing fitness landscapes associated with polymorphic adaptive traits enables investigation of mechanisms allowing transitions between fitness peaks. Here, we explore how natural selection can promote genetic mechanisms preventing heterozygous phenotypes from falling into non-adaptive valleys. Polymorphic mimicry is an ideal system to inves...

Learning, defined as a change in behaviour evoked by experience, has hitherto been investigated almost exclusively in multicellular neural organisms. Evidence for learning in non-neural multicellular organisms is scant, and only a few unequivocal reports of learning have been described in single-celled organisms. Here we demonstrate habituation, an...

Independent evolution of similar traits in lineages inhabiting similar environments (convergent or repeated evolution) is often taken as evidence for adaptation by natural selection, and used to illustrate the predictability of evolution. Yet convergence is rarely perfect for two reasons. First, environments may not be as similar as they appear. Se...

The diversity of insect eggs is astounding but still largely unexplained. Here, we apply phylogenetic analyses to 208 species of stick and leaf insects, coupled with physiological measurements of metabolic rate and water loss on five species, to evaluate classes of factors that may drive egg morphological diversification: life history constraints,...

Junior homonomy warrants a replacement name for Ramulus lineatus (Liu & Cai, 1992) (Phasmatodea: Phasmatidae)

The diversity of insect eggs is astounding but still largely unexplained. Here, we apply phylogenetic analyses to over 210 species of stick and leaf insects (order Phasmatodea), coupled with physiological measurements of metabolic rate and water loss, to evaluate several major classes of factors that may drive egg morphological diversification: lif...

Independent evolution of similar traits in lineages inhabiting similar environments (convergent evolution) is often taken as evidence for adaptation by natural selection, and used to illustrate the predictability of evolution. Yet convergence is rarely perfect. Environments may not be as similar as they appear (e.g., habitats scored the same may be...

Rhinoceros beetle ( Trypoxylus dichotomus ) males have pitchfork-shaped head horns, which they use to pry rival males from the trunks of trees. In the largest males these horns can be three times the length of horns in the two closest sister species. Because this weapon functions as a lever, longer horns should lift with less force than shorter hor...

How has the diversity of life forms come to be? This question is at the core of evolutionary biology and can be addressed at different scales: by studying the processes that drive modifications within populations of organisms generation after generation (microevolution), or by investigating patterns of changes on the tree of life over long periods...

Membrane lipids, and especially phosphoinositides, are differentially enriched within the eukaryotic endomembrane system. This generates a landmark code by modulating the properties of each membrane. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P 2 ] specifically accumulates at the plasma membrane in yeast, animal, and plant cells, where it regula...

Background In most arthropods, adult females are larger than males, and male competition is a race to quickly locate and mate with scattered females (scramble competition polygyny). Variation in body size among males may confer advantages that depend on context. Smaller males may be favored due to more efficient locomotion leading to higher mobilit...

Membranes lipids, and especially phosphoinositides, are differentially enriched within the eukaryotic endomembrane system. This generates a landmark code by modulating the properties of each membrane. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P 2 ] specifically accumulates at the plasma membrane in yeast, animal and plant cells, where it regula...

The habitat and resource use of females critically affects their pattern of distribution and consequently their monoposibility by males and the mating system of a species. Shifts in habitat use are therefore likely to be associated with changes in mating system and sexual selection acting on males' phenotypes, consequently affecting patterns of sex...

Exaggerated weapons of sexual selection often diverge more rapidly and dramatically than other body parts, suggesting that relevant agents of selection may be discernible in contemporary populations. We examined the ecology, reproductive behavior, and strength of sexual selection on horn length in five recently diverged rhinoceros beetle (Trypoxylu...

A current evolutionary hypothesis predicts that the most extreme forms of animal weaponry arise in systems where combatants fight each other one-to-one, in duels. It has also been suggested that arms races in human interstate conflicts are more likely to escalate in cases where there are only two opponents. However, directly testing whether duels m...

Sexually selected weapons often function as honest signals of fighting ability. If poor-quality individuals produce high-quality weapons, then receivers should focus on other, more reliable signals. Cost is one way to maintain signal integrity. The costs of weapons tend to increase with relative weapon size, and thereby restrict large weapons to hi...

The size of sexually selected weapons and their performance in battle are both critical to reproductive success, yet these traits are often in opposition. Bigger weapons make better signals. However, due to the mechanical properties of weapons as lever systems, increases in size may inhibit other metrics of performance as different components of th...

Schematic of constructed force transducer. A) Rigid metal bar used to stabilize the transducer stationary during trials. B) Flexible, brass arms that bend during squeezing trials. C) Needles that the animals squeeze during trials. Squeezing force (red) causes deformation in brass arms (B). Deformation is recorded by strain gauges (blue) in a full b...

Summary of morphological measurements. (DOCX)

Lever components of A) Sagra femorata and B) Narnia femorata hindlimbs. (TIFF)

Oviposition sites may be challenging and energetically costly to access for females in the presence of competitors contesting that resource. Additionally, oviposition sites may be difficult to reach, and penetrating a hard substrate can raise energy costs. In the seeddrilling parasitic wasp Eupelmus vuilleti, females actively fight with conspecific...