Regulatory Changes in the Fatty Acid Elongase Underlie the Evolution of Sex-specific Pheromone Profiles in .

Pheromones play a key role in regulating sexual behavior throughout the animal kingdom. In and other insects, many cuticular hydrocarbons (CHCs) are sexually dimorphic, and some are known to perform pheromonal functions. However, the genetic control of sex-specific CHC production is not understood outside of the model species .

Odorant receptors tuned to isothiocyanates in and their evolutionary expansion in herbivorous relatives.

Plants release complex volatile compounds to attract mutualists, deter herbivores, and deceive pollinators. Here, we used herbivorous specialist flies that feed on mustard plants ( spp.) and microbe-feeding species ( and spp.

The Gongora gibba genome assembly provides new insights into the evolution of floral scent in male euglossine bee-pollinated orchids.

Orchidaceae is one of the most prominent flowering plant families, with many species exhibiting highly specialized reproductive and ecological adaptations. An estimated 10% of orchid species in the American tropics are pollinated by scent-collecting male euglossine bees; however, to date, there are no published genomes of species within this pollination syndrome. In this study, we present the first draft genome of an epiphytic orchid from the genus Gongora, a representative of the male euglossine bee-pollinated subtribe Stanhopeinae.

Evolution of Acquired Perfumes and Endogenous Lipid Secretions in Orchid Bees.

Male orchid bees are unique in the animal kingdom for making perfumes that function as sex pheromone. Males collect volatile chemicals from the environment in the neotropical forests, including floral and non-floral sources, creating complex but species-specific blends. Male orchid bees exhibit several adaptations to facilitate perfume collection and storage.

Evidence for Reductions in Physical and Chemical Plant Defense Traits in Island Flora.

Reduced defense against large herbivores has been suggested to be part of the "island syndrome" in plants. However, empirical evidence for this pattern is mixed. In this paper, we present two studies that compare putative physical and chemical defense traits from plants on the California Channel Islands and nearby mainland based on sampling of both field and common garden plants.

Chemical species recognition in an adaptive radiation of Hawaiian spiders (Araneae: Tetragnathidae).

Studies of adaptive radiations have played a central role in our understanding of reproductive isolation. Yet the focus has been on human-biased visual and auditory signals, leaving gaps in our knowledge of other modalities. To date, studies on chemical signals in adaptive radiations have focused on systems with multimodal signalling, making it difficult to isolate the role chemicals play in reproductive isolation.

The transcriptomic signature of adaptations associated with perfume collection in orchid bees.

Secondary sexual traits can convey information on mate quality with the signal honesty maintained by the costly nature of trait expression. Mating signals are also often underpinned by physiological, morphological, and behavioural adaptations, which may require the evolution of novelty, but the genetic basis in many cases is unknown. In orchid bees, males acquire chemical compounds from the environment that act as pheromone-like bouquets (perfumes) during courtship displays.

Individual Variation in Male Pheromone Production in Xylocopa sonorina Correlates with size and Gland Color.

Sex pheromones are species-specific chemical signals that facilitate the location, identification, and selection of mating partners. These pheromones can vary between individuals, and act as signals of mate quality. Here, we investigate the variation of male pheromones in the mesosomal glands of the large carpenter bee Xylocopa sonorina, within a Northern California population.

Macroevolution of floral scent chemistry across radiations of male euglossine bee-pollinated plantsMacroevolución de olores florales a través de radiaciones de plantas polinizadas por abejas euglosinas machosMacroevolução dos voláteis florais em radiações de plantas polinizadas por machos de abelhas Euglossini.

Floral volatiles play key roles as signaling agents that mediate interactions between plants and animals. Despite their importance, few studies have investigated broad patterns of volatile variation across groups of plants that share pollinators, particularly in a phylogenetic context. The "perfume flowers," Neotropical plant species exhibiting exclusive pollination by male euglossine bees in search of chemical rewards, present an intriguing system to investigate these patterns due to the unique function of their chemical phenotypes as both signaling agents and rewards.

Biogeography: The origin and spread of bee lineages.

Where and when bees originated and how they dispersed and diversified across ancient continents has remained ambiguous. A new study that combines phylogenetics with fossil data reconstructs the origin and diversification of bees across geological time and space.

Function of environment-derived male perfumes in orchid bees.

Perfume making in male orchid bees is a unique behavior that has given rise to an entire pollination syndrome in the neotropics. Male orchid bees concoct and store species-specific perfume mixtures in specialized hind-leg pockets using volatiles acquired from multiple environmental sources, including orchid flowers. However, the function and the ultimate causes of this behavior have remained elusive.

Seasonal stability and species specificity of environmentally acquired chemical mating signals in orchid bees.

Traits that mediate reproductive isolation between species, such as those involved in mate choice and/or recognition, are predicted to experience stabilizing selection towards the species mean. Male orchid bees collect chemical compounds from many sources, such as plants and fungi, which they use as a perfume signal (pheromone) during courtship display, and are suggested to contribute to reproductive isolation between species. Environmentally acquired signals are more prone to variation as source availability can vary through space and time.

Population genetics of a recent range expansion and subsequent loss of migration in monarch butterflies.

Range expansions-whether permanent or transient-strongly influence the distribution of genetic variation in space. Monarch butterflies are best known for long-distance seasonal migration within North America but are also established as nonmigratory populations around the world, including on Pacific Islands. Previous research has highlighted stepwise expansion across the Pacific, though questions remain about expansion timing and the population genetic consequences of migration loss.

Experimental disruption of social structure reveals totipotency in the orchid bee, Euglossa dilemma.

Eusociality has evolved multiple times across the insect phylogeny. Social insects with greater levels of social complexity tend to exhibit specialized castes with low levels of individual phenotypic plasticity. In contrast, species with simple social groups may consist of totipotent individuals that transition among behavioral and reproductive states.

Evolution of Olfactory Receptors Tuned to Mustard Oils in Herbivorous Drosophilidae.

The diversity of herbivorous insects is attributed to their propensity to specialize on toxic plants. In an evolutionary twist, toxins betray the identity of their bearers when herbivores coopt them as cues for host-plant finding, but the evolutionary mechanisms underlying this phenomenon are poorly understood. We focused on Scaptomyza flava, an herbivorous drosophilid specialized on isothiocyanate (ITC)-producing (Brassicales) plants, and identified Or67b paralogs that were triplicated as mustard-specific herbivory evolved.

The Birth-and-Death Evolution of Cytochrome P450 Genes in Bees.

The birth-and-death model of multigene family evolution describes how gene families evolve and diversify through duplication and deletion. The cytochrome P450s are one of the most diverse and well-studied multigene families, involved in both physiological and xenobiotic functions. Extensive studies of insect P450 genes have demonstrated their role in insecticide resistance.

Social Behavior, Ovary Size, and Population of Origin Influence Cuticular Hydrocarbons in the Orchid Bee .

AbstractCuticular hydrocarbons (CHCs) are waxy compounds on the surface of insects that prevent desiccation and frequently serve as chemical signals mediating social and mating behaviors. Although their function in eusocial species has been heavily investigated, little is known about the evolution of CHC-based communication in species with simpler forms of social organization lacking specialized castes. Here we investigate factors shaping CHC variation in the orchid bee , which forms casteless social groups of two to three individuals.

Two centuries of monarch butterfly collections reveal contrasting effects of range expansion and migration loss on wing traits.

Migratory animals exhibit traits that allow them to exploit seasonally variable habitats. In environments where migration is no longer beneficial, such as oceanic islands, migration-association traits may be selected against or be under relaxed selection. Monarch butterflies are best known for their continent-scale migration in North America but have repeatedly become established as nonmigrants in the tropical Americas and on Atlantic and Pacific Islands.

Selection and hybridization shaped the rapid spread of African honey bee ancestry in the Americas.

Recent biological invasions offer 'natural' laboratories to understand the genetics and ecology of adaptation, hybridization, and range limits. One of the most impressive and well-documented biological invasions of the 20th century began in 1957 when Apis mellifera scutellata honey bees swarmed out of managed experimental colonies in Brazil. This newly-imported subspecies, native to southern and eastern Africa, both hybridized with and out-competed previously-introduced European honey bee subspecies.

The evolution of sexual signaling is linked to odorant receptor tuning in perfume-collecting orchid bees.

Sexual signaling is an important reproductive barrier known to evolve early during the formation of new species, but the genetic mechanisms that facilitate the divergence of sexual signals remain elusive. Here we isolate a gene linked to the rapid evolution of a signaling trait in a pair of nascent neotropical orchid bee lineages, Euglossa dilemma and E. viridissima.

Host plant adaptation during contemporary range expansion in the monarch butterfly.

Herbivores that have recently expanded their host plant ranges provide opportunities to test hypotheses about the evolution of host plant specialization. Here, we take advantage of the contemporary global range expansion of the monarch butterfly (Danaus plexippus) and conduct a reciprocal rearing experiment involving monarch populations with divergent host plant assemblages. Specifically, we ask the following questions: (1) Do geographically disparate populations of monarch butterflies show evidence for local adaptation to their host plants? If so, what processes contribute to this pattern? (2) How is dietary breadth related to performance across multiple host species in monarch populations? (3) Does the coefficient of variation in performance vary across sympatric versus allopatric hosts? We find evidence for local adaptation in larval growth rate and survival based on sympatric/allopatric contrasts.

Sociality emerges from solitary behaviours and reproductive plasticity in the orchid bee Euglossa dilemma.

The evolution of eusociality and sterile worker castes represents a major transition in the history of life. Despite this, little is known about the mechanisms involved in the initial transition from solitary to social behaviour. It has been hypothesized that plasticity from ancestral solitary life cycles was coopted to create queen and worker castes in insect societies.

Genetic and chemical divergence among host races of a socially parasitic ant.

Host-parasite associations facilitate the action of reciprocal selection and can drive rapid evolutionary change. When multiple host species are available to a single parasite, parallel specialization on different hosts may promote the action of diversifying natural selection and divergence via host race formation. Here, we examine a population of the kidnapper ant () that is an obligate social parasite of three sympatric ant species: , , and (formerly ).

Sexual dimorphism in visual and olfactory brain centers in the perfume-collecting orchid bee Euglossa dilemma (Hymenoptera, Apidae).

Insect mating behavior is controlled by a diverse array of sex-specific traits and strategies that evolved to maximize mating success. Orchid bees exhibit a unique suite of perfume-mediated mating behaviors. Male bees collect volatile compounds from their environment to concoct species-specific perfume mixtures that are presumably used to attract conspecific females.

The evolution of floral signals in relation to range overlap in a clade of California Jewelflowers (Streptanthus s.l.).

Because of their function as reproductive signals in plants, floral traits experience distinct selective pressures related to their role in speciation, reinforcement, and prolonged coexistence with close relatives. However, few studies have investigated whether population-level processes translate into detectable signatures at the macroevolutionary scale. Here, we ask whether patterns of floral trait evolution and range overlap across a clade of California Jewelflowers reflect processes hypothesized to shape floral signal differentiation at the population level.