Characterization of Squamate Olfactory Receptor Genes and Their Transcripts by the High-Throughput Sequencing Approach

The olfactory receptor (OR) genes represent the largest multigene family in the genome of terrestrial vertebrates. Here, the high-throughput next-generation sequencing (NGS) approach was applied to characterization of OR gene repertoires in the green anole lizard Anolis carolinensis and the Japanese four-lined ratsnake Elaphe quadrivirgata. Tagged polymerase chain reaction (PCR) products amplified from either genomic DNA or cDNA of the two species were used for parallel pyrosequencing, assembling, and screening for errors in PCR and pyrosequencing. Starting from the lizard genomic DNA, we accurately identified 56 of 136 OR genes that were identified from its draft genome sequence. These recovered genes were broadly distributed in the phylogenetic tree of vertebrate OR genes without severe biases toward particular OR families. Ninety-six OR genes were identified from the ratsnake genomic DNA, implying that the snake has more OR gene loci than the anole lizard in response to an increased need for the acuity of olfaction. This view is supported by the estimated number of OR genes in the Burmese python's draft genome (∼280), although squamates may generally have fewer OR genes than terrestrial mammals and amphibians. The OR gene repertoire of the python seems unique in that many class I OR genes are retained. The NGS approach also allowed us to identify candidates of highly expressed and silent OR gene copies in the lizard's olfactory epithelium. The approach will facilitate efficient and parallel characterization of considerable unbiased proportions of multigene family members and their transcripts from nonmodel organisms

Eliciting a predatory response in the eastern corn snake (Pantherophis guttatus) using live and inanimate sensory stimuli: implications for managing invasive populations

North America's Eastern corn snake (Pantherophis guttatus) has been introduced to several islands throughout the Caribbean and Australasia where it poses a significant threat to native wildlife. Invasive snake control programs often involve trapping with live bait, a practice that, as well as being costly and labour intensive, raises welfare and ethical concerns. This study assessed corn snake response to live and inanimate sensory stimuli in an attempt to inform possible future trapping of the species and the development of alternative trap lures. We exposed nine individuals to sensory cues in the form of odour, visual, vibration and combined stimuli and measured the response (rate of tongue-flick [RTF]). RTF was significantly higher in odour and combined cues treatments, and there was no significant difference in RTF between live and inanimate cues during odour treatments. Our findings suggest chemical cues are of primary importance in initiating predation and that an inanimate odour stimulus, absent of simultaneous visual and vibratory cues, is a potential low-cost alternative trap lure for the control of invasive corn snake populations

Invasive termites in a changing climate: A global perspective.

Termites are ubiquitous insects in tropical, subtropical, and warm temperate regions and play an important role in ecosystems. Several termite species are also significant economic pests, mainly in urban areas where they attack human-made structures, but also in natural forest habitats. Worldwide, approximately 28 termite species are considered invasive and have spread beyond their native ranges, often with significant economic consequences. We used predictive climate modeling to provide the first global risk assessment for 13 of the world's most invasive termites. We modeled the future distribution of 13 of the most serious invasive termite species, using two different Representative Concentration Pathways (RCPs), RCP 4.5 and RCP 8.5, and two projection years (2050 and 2070). Our results show that all but one termite species are expected to significantly increase in their global distribution, irrespective of the climatic scenario and year. The range shifts by species (shift vectors) revealed a complex pattern of distributional changes across latitudes rather than simple poleward expansion. Mapping of potential invasion hotspots in 2050 under the RCP 4.5 scenario revealed that the most suitable areas are located in the tropics. Substantial parts of all continents had suitable environmental conditions for more than four species simultaneously. Mapping of changes in the number of species revealed that areas that lose many species (e.g., parts of South America) are those that were previously very species-rich, contrary to regions such as Europe that were overall not among the most important invasion hotspots, but that showed a great increase in the number of potential invaders. The substantial economic and ecological damage caused by invasive termites is likely to increase in response to climate change, increased urbanization, and accelerating economic globalization, acting singly or interactively