Comparación de la eficiencia del método de captura-marcaje-recaptura y de registro indirecto del curí silvestre (Cavia anolaimae) en la reserva forestal municipal de Cogua, Cundinamarca

Uno de los aspectos clave para el éxito de los estudios en fauna silvestre es el uso de métodos de muestreo eficientes que permitan la consecución de los objetivos planteados. Por esta razón se hace necesaria la evaluación y comparación de métodos que establezca de manera clara y precisa su eficiencia y en consecuencia los resultados conduzcan a una elección apropiada. El objetivo principal del estudio fue comparar la eficiencia del método de captura-marcaje-recaptura y de registro indirecto de Cavia anolaimae en la Reserva Forestal Municipal de Cogua. El trabajo en campo se desarrolló durante los meses de febrero a abril de 2008. Se emplearon dos tipos de trampas para cada método con 20 repeticiones de cada una: trampas Sherman y Pitfall para el método de captura y trampas de tubo y huelleros para el método de registro indirectoOne of the key to the success of studies in wildlife is the use of sampling methods that allow the efficient achievement of the goals. For this reason the evaluation and comparison of methods are necessary to set out clearly and precisely their efficiency and therefore, the findings lead to an appropriate choice. The main objective of the study was to evaluate the efficiency of the method of capture-mark-recapture and indirect registration of Cavia anolaimae in the Municipal Forest Reserve of Cogua. The fieldwork was conducted during February to April 2008. There were used two types of traps for each method with 20 repetitions of each one: Sherman and Pitfall traps for the trapping method, and tracking tube and footprinters for indirect register.Biólogo (a)Pregrad

Predator-Induced Plasticity on Warning Signal and Larval Life-History Traits of the Aposematic Wood Tiger Moth, Arctia plantaginis

Correction Frontiers in Ecology and Evolution Volume 9 Article Number 737651 DOI 10.3389/fevo.2021.737651 Published JUL 29 2021Predator-induced plasticity in life-history and antipredator traits during the larval period has been extensively studied in organisms with complex life-histories. However, it is unclear whether different levels of predation could induce warning signals in aposematic organisms. Here, we investigated whether predator-simulated handling affects warning coloration and life-history traits in the aposematic wood tiger moth larva, Arctia plantaginis. As juveniles, a larger orange patch on an otherwise black body signifies a more efficient warning signal against predators but this comes at the costs of conspicuousness and thermoregulation. Given this, one would expect that an increase in predation risk would induce flexible expression of the orange patch. Prior research in this system points to plastic effects being important as a response to environmental changes for life history traits, but we had yet to assess whether this was the case for predation risk, a key driver of this species evolution. Using a full-sib rearing design, in which individuals were reared in the presence and absence of a non-lethal simulated bird attack, we evaluated flexible responses of warning signal size (number of orange segments), growth, molting events, and development time in wood tiger moths. All measured traits except development time showed a significant response to predation. Larvae from the predation treatment developed a more melanized warning signal (smaller orange patch), reached a smaller body size, and molted more often. Our results suggest plasticity is indeed important in aposematic organisms, but in this case may be complicated by the trade-off between costly pigmentation and other life-history traits.Peer reviewe

Clustering of loci controlling species differences in male chemical bouquets of sympatric Heliconius butterflies

The degree to which loci promoting reproductive isolation cluster in the genome-that is, the genetic architecture of reproductive isolation-can influence the tempo and mode of speciation. Tight linkage between these loci can facilitate speciation in the face of gene flow. Pheromones play a role in reproductive isolation in many Lepidoptera species, and the role of endogenously produced compounds as secondary metabolites decreases the likelihood of pleiotropy associated with many barrier loci. Heliconius butterflies use male sex pheromones to both court females (aphrodisiac wing pheromones) and ward off male courtship (male-transferred antiaphrodisiac genital pheromones), and it is likely that these compounds play a role in reproductive isolation between Heliconius species. Using a set of backcross hybrids between H. melpomene and H. cydno, we investigated the genetic architecture of putative male pheromone compound production. We found a set of 40 significant quantitative trait loci (QTL) representing 33 potential pheromone compounds. QTL clustered significantly on two chromosomes, chromosome 8 for genital compounds and chromosome 20 for wing compounds, and chromosome 20 was enriched for potential pheromone biosynthesis genes. There was minimal overlap between pheromone QTL and known QTL for mate choice and color pattern. Nonetheless, we did detect linkage between a QTL for wing androconial area and optix, a color pattern locus known to play a role in reproductive isolation in these species. This tight clustering of putative pheromone loci might contribute to coincident reproductive isolating barriers, facilitating speciation despite ongoing gene flow.Peer reviewe

A novel terpene synthase controls differences in anti-aphrodisiac pheromone production between closely related Heliconius butterflies.

Plants and insects often use the same compounds for chemical communication, but not much is known about the genetics of convergent evolution of chemical signals. The terpene (E)-β-ocimene is a common component of floral scent and is also used by the butterfly Heliconius melpomene as an anti-aphrodisiac pheromone. While the biosynthesis of terpenes has been described in plants and microorganisms, few terpene synthases (TPSs) have been identified in insects. Here, we study the recent divergence of 2 species, H. melpomene and Heliconius cydno, which differ in the presence of (E)-β-ocimene; combining linkage mapping, gene expression, and functional analyses, we identify 2 novel TPSs. Furthermore, we demonstrate that one, HmelOS, is able to synthesise (E)-β-ocimene in vitro. We find no evidence for TPS activity in HcydOS (HmelOS ortholog of H. cydno), suggesting that the loss of (E)-β-ocimene in this species is the result of coding, not regulatory, differences. The TPS enzymes we discovered are unrelated to previously described plant and insect TPSs, demonstrating that chemical convergence has independent evolutionary origins

A novel terpene synthase controls differences in anti-aphrodisiac pheromone production between closely related Heliconius butterflies

Plants and insects often use the same compounds for chemical communication, but not much is known about the genetics of convergent evolution of chemical signals. The terpene (E)-beta-ocimene is a common component of floral scent and is also used by the butterfly Heliconius melpomene as an anti-aphrodisiac pheromone. While the biosynthesis of terpenes has been described in plants and microorganisms, few terpene synthases (TPSs) have been identified in insects. Here, we study the recent divergence of 2 species, H. melpomene and Heliconius cydno, which differ in the presence of (E)-beta-ocimene; combining linkage mapping, gene expression, and functional analyses, we identify 2 novel TPSs. Furthermore, we demonstrate that one, HmelOS, is able to synthesise (E)-beta-ocimene in vitro. We find no evidence for TPS activity in HcydOS (HmelOS ortholog of H. cydno), suggesting that the loss of (E)-beta-ocimene in this species is the result of coding, not regulatory, differences. The TPS enzymes we discovered are unrelated to previously described plant and insect TPSs, demonstrating that chemical convergence has independent evolutionary origins.Peer reviewe

A novel terpene synthase controls differences in anti-aphrodisiac pheromone production between closely related Heliconius butterflies

Funder: Deutsche Forschungsgemeinschaft; Grant(s): Emmy Noether Fellowship GZ:ME4845/1-1Funder: Jane ja Aatos Erkon Säätiö; funder-id: http://dx.doi.org/10.13039/501100004012Funder: Smithsonian Tropical Research Institute; funder-id: http://dx.doi.org/10.13039/100009201Plants and insects often use the same compounds for chemical communication, but not much is known about the genetics of convergent evolution of chemical signals. The terpene (E)-β-ocimene is a common component of floral scent and is also used by the butterfly Heliconius melpomene as an anti-aphrodisiac pheromone. While the biosynthesis of terpenes has been described in plants and microorganisms, few terpene synthases (TPSs) have been identified in insects. Here, we study the recent divergence of 2 species, H. melpomene and Heliconius cydno, which differ in the presence of (E)-β-ocimene; combining linkage mapping, gene expression, and functional analyses, we identify 2 novel TPSs. Furthermore, we demonstrate that one, HmelOS, is able to synthesise (E)-β-ocimene in vitro. We find no evidence for TPS activity in HcydOS (HmelOS ortholog of H. cydno), suggesting that the loss of (E)-β-ocimene in this species is the result of coding, not regulatory, differences. The TPS enzymes we discovered are unrelated to previously described plant and insect TPSs, demonstrating that chemical convergence has independent evolutionary origins

Predator-induced plasticity on the life-history and antipredator defenses of the aposematic wood tiger moth larva

Defense mechanisms in organisms evolve as a response of predator-prey interactions, reducing prey mortality. Flexibility in antipredator strategies due to heterogeneous environments can be explained by phenotypic plasticity. This plasticity can be important for aposematic organisms where variation in the warning signal within a population is considered puzzling. In aposematism, monomorphism is expected because the predator better learns to avoid the unprofitable prey associated with a conspicuous signal and tends to generalize the negative experience to nearby stimulus. Thus, selection should favour the most common and conspicuous warning signal leading to positive frequency-dependent survival selection. I examined predator-induced plasticity on antipredator defenses of the aposematic wood tiger moth larva, Arctia plantaginis. The main defense of the larva is the continuous warning signal comprising a hairy black body and an orange patch on the dorsal part. A large orange patch has been related with a more efficient antipredator function, while a small patch with efficiency in thermoregulation and immunity response. Given this, I hypothesized that predation would induce a plastic response in warning signal size. Due to the potential importance or interaction of other antipredator defenses such as body size, development time and behaviour I also studied their plastic response to predation. I expected a positive plastic response from the larvae under pr edation risk. Based on general theory and past results in the system I also predicted that under predation larvae would develop a smaller body size, a faster development time with less instars and slower escape behaviour. I reared larvae from 20 families in a split-design experiment. Individuals from each family were evenly split and reared in two environments. In one, the larvae were exposed to a simulated bird attack, whereas in the other, the larvae were left to develop in normal conditions. Overall I found predation induced a significant plastic response in the orange warning signal size, body size and number of moulting events. It also affected overall survival. However, predation did not have a significant effect on the larval development time. The escape behaviour was also plastic and there was a significant interaction between families and the treatment, suggesting that not all organisms responded similarly to predation. I also find a significant family effect, meaning that families in the study expressed differences in the mean value for a specific trait. In conclusion, the traits showed to differ in the plastic responsiveness to predation. This provides an insight about the selection pressures that constraint the plastic response. For instance, the development time showed to be a trait less sensitive, suggesting that for organisms that are seasonally constrained, time to metamorphosis is more critical than the risk of predation

A major locus controls a biologically active pheromone component in Heliconius melpomene

Understanding the production, response, and genetics of signals used in mate choice can inform our understanding of the evolution of both intraspecific mate choice and reproductive isolation. Sex pheromones are important for courtship and mate choice in many insects, but we know relatively little of their role in butterflies. The butterfly Heliconius melpomene uses a complex blend of wing androconial compounds during courtship. Electroantennography in H. melpomene and its close relative Heliconius cydno showed that responses to androconial extracts were not species specific. Females of both species responded equally strongly to extracts of both species, suggesting conservation of peripheral nervous system elements across the two species. Individual blend components provoked little to no response, with the exception of octadecanal, a major component of the H. melpomene blend. Supplementing octadecanal on the wings of octadecanal-rich H. melpomene males led to an increase in the time until mating, demonstrating the bioactivity of octadecanal in Heliconius. Using quantitative trait locus (QTL) mapping, we identified a single locus on chromosome 20 responsible for 41% of the parental species' difference in octadecanal production. This QTL does not overlap with any of the major wing color or mate choice loci, nor does it overlap with known regions of elevated or reduced F-ST. A set of 16 candidate fatty acid biosynthesis genes lies underneath the QTL. Pheromones in Heliconius carry information relevant for mate choice and are under simple genetic control, suggesting they could be important during speciation.Peer reviewe