Anurans are known to detect vibrations, but few studies explore relationships between vibrations and resultant behaviors. We studied the reaction of calling captive-bred male midwife toads (
Alytes ...obstetricans
) to the randomized playback of a vibrational crescendo stimulus train. We considered two sources of natural abiotic vibrational stimuli: rainfall and wind. Rainfall was expected to induce calling and wind was expected to inhibit it. Playback experiments with two synthetic tones (200 Hz and 300 Hz) tested the sensitivity to pure tones and could possibly reveal a hearing sensitivity trend between these frequencies. The toads did not increase call rate in response to rainfall vibrations and only one of the five wind stimulus levels caused a significant decrease in call rate. This limited response could be explained, because the tested toads came from a captive population, where emergence may not be mediated by rainfall vibrations. We found that
A. obstetricans
is highly sensitive to very low frequencies, which could explain the sensitivity observed to vibrational stimuli. Playback of a random crescendo stimulus train proves to be a valid approach for addressing behavioral questions. However, the use of a captive population may have been a limitation in the clarity of the results.
The increasing demand for safe and sustainably produced food is leading to the development of strategies of pest control alternative to chemicals. One innovative method is Vibrational Mating ...Disruption (VMD) to disrupt insect communication in plants. VMD was proven effective in preventing mating of the grapevine pest Scaphoideus titanus, vector of flavescence dorée. However, the stress induced by VMD on the target species has the potential to influence other crucial aspects of the insect biology and ethology. Therefore, the goal of this study was to understand side effects of VMD on the flight activity and oviposition of S. titanus. The results of our experiments conducted in the greenhouse showed that in the presence of a receptive female, males fly more if exposed to vibrations than in the silent control but not differently from singles males in silence. Surprisingly, we found that also females subjected to VMD fly more than in the silence. Regarding oviposition, we found that mated females exposed to vibrations and single females (unmated) laid significantly fewer eggs than mated females in silence. In conclusion, this study shows the potential of VMD to interfere, besides with mating, with other important biological aspects of the pest species.
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•Vibrational Mating Disruption (VMD) increases flight activity of Scaphoideus titanus males and females.•VMD reduces oviposition in S. titanus.•VMD could affect pest population density by interfering with multiple behaviors of target species.
Anthropogenic noise is widespread in nature and has been shown to produce a plethora of impacts on wildlife. Sounds play a fundamental role in the lives of amphibians, with species relying on ...acoustic communication for social and reproductive behaviour, and thus noise can potentially interfere with these activities. Here, we provide a literature review on the effects of anthropogenic noise on anuran amphibians, based on 32 studies (63 species from 14 families) that document noise-driven changes in species behaviour, physiology and ecology caused by urbanisation, transportation and energy production. Experimental and observational studies found evidence that both airborne and seismic anthropogenic noise influence anuran calling activity, with consequences in mate selection, and induce physiological changes including increased stress, suppressed immune function and colouration changes. Negative noise effects in species abundance and attendance over the reproductive season were reported. Even though adaptations and behavioural adjustments enable species to respond to these noises, it is yet to be understood whether these changes alleviate the negative impacts. Furthermore, collaborative efforts between scientists, stakeholders and private/public institutions are imperative to create conservation guidelines and legal instruments to be implemented during urban expansion projects and mitigate the effects of noise pollution on amphibian anurans.
Abstract Abundance on and access time to the host plant are the pivotal factors in Xylella fastidiosa transmission to olive by the meadow spittlebug Philaenus spumarius . Therefore, olive varieties ...suitable for the vectors, i.e., plants providing all the necessary cues to the insect for their location, settling and acceptance, and devoid of antixenotic defenses, could be more susceptible to infection than varieties non- or less suitable for the vector. Here we evaluated whether a bacterium-susceptible olive variety, Ogliarola Salentina, could be a more suitable host for P. spumarius than the two resistant varieties Leccino and FS-17. We carried out: (i) an evaluation of between-hosts and within-host preference; (ii) an insect survival analysis; (iii) an Electrical Penetration Graph (EPG)-assisted analysis of the probing behavior; (iv) light microscopy of the tissues the spittlebugs had access to; (v) an analysis of the xylem sap primary metabolites. In choice tests, the insect exhibited a significant preference for Ogliarola Salentina. In addition, spittlebugs displayed longer xylem sap ingestion bouts on the bacterium-susceptible variety compared to resistant genotypes, possibly because of differences in the xylem sap chemical profile rather than xylem anatomy. Spittlebugs preference for Ogliarola over both Leccino and FS-17 could be a relevant and so far overlooked component of the low disease prevalence in these two olive varieties reported in Southern Italian olive orchards. Overall, our data point toward the importance of incorporating studies on vector-plant interaction and host traits of resistance to the vector in research on genotypes resistant to X. fastidiosa .
We provide detailed descriptions of the poorly known advertisement calls of Eleutherodactylus abbotti, E. flavescens and E. inoptatus, three rain frogs endemic to the Caribbean island of Hispaniola. ...We compare these three advertisement calls to those of closely related and/or geographically proximate Eleutherodactylus species. The call of E. abbotti lasts 0.5-6 s and consists of four notes that differ in amplitude and duration, with a mean dominant frequency of 4527 Hz. In turn, the call of E. flavescens, endemic to the Dominican Republic, lasts 0.02-0.09 s and consists of two different notes with dominant frequencies of 2288 and 3025 Hz. In contrast, the call of E. inoptatus lasts 0.25-0.39 s and is composed of a single multi-pulsed note with two harmonics, the first one with a dominant frequency of 660 Hz and the second one with a dominant frequency of 1220 Hz. These congeneric species occur sympatrically over large areas below 1000 m elevation and are commonly encountered together, which suggests that, in addition to interspecific variation (e.g. body size), the remarkable differences in their calls (e.g. dominant frequency) may be due to partitioning of the acoustic environment.
In this study, we provide detailed descriptions of the previously unknown advertisement calls of Osteopilus dominicensis and Hypsiboas heilprini, as well as a complete redescription of that of O. ...pulchrilineatus, three of the four hylid frogs known from the Caribbean island of Hispaniola. The call of O. dominicensis is composed of a single multi-pulsed note with a mean dominant frequency of 2058 Hz. In contrast, the call of O. pulchrilineatus consists of two different pulsed notes (the second repeated many times in one call) with a mean dominant frequency of 2950 and 2060 Hz, respectively. The call of H. heilprini, in turn, is a trill consisting of multi-pulsed notes (emitted in a consecutive series) with a mean dominant frequency of 1738 Hz. We compare these three calls to those of closely related species.
The most common method for identifying individual amphibians is toe-clipping (TC), whereby captured individuals are marked by a unique combination of amputated phalanges that corresponds to a unique ...alphanumeric code. However, ethical and methodological objections to this method have been raised and there is broad interest in developing alternative methods. One alternative is to use photo-identification methods (PIMs) to identify individuals based on their natural markings. We tested the efficacy of TC and two PIMs â visual matching (VM) and computer-assisted matching (CAM) using the software Wild-ID â in identifying individual adults of the endangered southern red-bellied toad, Melanophryniscus cambaraensis. We collected data over 5 mo at Floresta Nacional de São Francisco de Paula, Rio Grande do Sul, Brazil. All specimens were toe-clipped and photographed. The total dataset included 492 captures of 147 individuals. VM was most accurate (99.4%), followed by TC (95.3%) and CAM (90.9%); VM was significantly more accurate than TC and CAM and TC was significantly more accurate than CAM. CAM accuracy diminished as dataset size increased but was considerably faster than VM. All CAM and VM errors were false negatives but involved different images; all TC errors were cross-identifications. Given that misidentifications occurred using both PIMs and TC, our results suggest that studies that require high accuracy should employ at least two methods to allow cross-validation. The performance of each method and the impacts of different kinds and rates of error on inferences depend on the organisms, field conditions, dataset sizes, and study questions. As such, researchers must carefully evaluate the trade-offs of each method before investing significant time and resources in collecting field data.
