A Receptor-Based Explanation for Tsetse Fly Catch Distribution between Coloured Cloth Panels and Flanking Nets

Tsetse flies transmit trypanosomes that cause nagana in cattle, and sleeping sickness in humans. Therefore, optimising visual baits to control tsetse is an important priority. Tsetse are intercepted at visual baits due to their initial attraction to the bait, and their subsequent contact with it due to landing or accidental collision. Attraction is proposed to be driven in part by a chromatic mechanism to which a UV-blue photoreceptor contributes positively, and a UV and a green photoreceptor contribute negatively. Landing responses are elicited by stimuli with low luminance, but many studies also find apparently strong landing responses when stimuli have high UV reflectivity, which would imply that UV wavelengths contribute negatively to attraction at a distance, but positively to landing responses at close range. The strength of landing responses is often judged using the number of tsetse sampled at a cloth panel expressed as a proportion of the combined catch of the cloth panel and a flanking net that samples circling flies. I modelled these data from two previously published field studies, using calculated fly photoreceptor excitations as predictors. I found that the proportion of tsetse caught on the cloth panel increased with an index representing the chromatic mechanism driving attraction, as would be expected if the same mechanism underlay both long- and close-range attraction. However, the proportion of tsetse caught on the cloth panel also increased with excitation of the UV-sensitive R7p photoreceptor, in an apparently separate but interacting behavioural mechanism. This R7p-driven effect resembles the fly open-space response which is believed to underlie their dispersal towards areas of open sky. As such, the proportion of tsetse that contact a cloth panel likely reflects a combination of deliberate landings by potentially host-seeking tsetse, and accidental collisions by those seeking to disperse, with a separate visual mechanism underlying each behaviour

Uncovering \u27Hidden\u27 Signals: Previously Presumed Visual Signals Likely Generate Air Particle Movement

Wolf spiders within the genus Schizocosa have become a model system for exploring the form and function of multimodal communication. In terms of male signaling, much past research has focused on the role and importance of dynamic and static visual and substrate-borne vibratory communication. Studies on S. retrorsa, however, have found that female-male pairs were able to successfully mate in the absence of both visual and vibratory stimuli, suggesting a reduced or non-existent role of these signaling modalities in this species. Given these prior findings, it has been suggested that S. retrorsa males may utilize an additional signaling modality during courtship-air particle movement, often referred to as near-field sound-which they likely produce with rapid leg waving and receive using thin filiform sensory hairs called trichobothria. In this study, we tested the role of air-particle movement in mating success by conducting two independent sets of mating trials with randomly paired S. retrorsa females and males in the dark and on granite (i.e., without visual or vibratory signals) in two different signaling environments-(i) without ( No Noise ) and (ii) with ( Noise ) introduced air-particle movement intended to disrupt signaling in that modality. We also ran foraging trials in No Noise/Noise environments to explore the impact of our treatments on overall behavior. Across both mating experiments, our treatments significantly impacted mating success, with more mating in the No Noise signaling environments compared to the Noise environments. The rate of leg waving-a previously assumed visual dynamic movement that has also been shown to be able to produce air particle displacement-was higher in the No Noise than Noise environments. Across both treatments, males with higher rates of leg waving had higher mating success. In contrast to mating trials results, foraging success was not influenced by Noise. Our results indicate that artificially induced air particle movement disrupts successful mating and alters male courtship signaling but does not interfere with a female\u27s ability to receive and assess the rate of male leg waving

Evaluation of improved coloured targets to control riverine tsetse in East Africa: A Bayesian approach

Background Riverine tsetse (Glossina spp.) transmit Trypanosoma brucei gambiense which causes Gambian Human African Trypanosomiasis. Tiny Targets were developed for cost-effective riverine tsetse control, and comprise panels of insecticide-treated blue polyester fabric and black net that attract and kill tsetse. Versus typical blue polyesters, two putatively more attractive fabrics have been developed: Vestergaard ZeroFly blue, and violet. Violet was most attractive to savannah tsetse using large targets, but neither fabric has been tested for riverine tsetse using Tiny Targets. Methods We measured numbers of G. f. fuscipes attracted to electrified Tiny Targets in Kenya and Uganda. We compared violets, Vestergaard blues, and a typical blue polyester, using three replicated Latin squares experiments. We then employed Bayesian statistical analyses to generate expected catches for future target deployments incorporating uncertainty in model parameters, and prior knowledge from previous experiments. Results Expected catches for average future replicates of violet and Vestergaard blue targets were highly likely to exceed those for typical blue. Accounting for catch variability between replicates, it remained moderately probable (70–86% and 59–84%, respectively) that a given replicate of these targets would have a higher expected catch than typical blue on the same day at the same site. Meanwhile, expected catches for average violet replicates were, in general, moderately likely to exceed those for Vestergaard blue. However, the difference in medians was small, and accounting for catch variability, the probability that the expected catch for a violet replicate would exceed a Vestergaard blue equivalent was marginal (46– 71%)

Reactive direction control for a mobile robot: A locust-like control of escape direction emerges when a bilateral pair of model locust visual neurons are integrated

Locusts possess a bilateral pair of uniquely identifiable visual neurons that respond vigorously to the image of an approaching object. These neurons are called the lobula giant movement detectors (LGMDs). The locust LGMDs have been extensively studied and this has lead to the development of an LGMD model for use as an artificial collision detector in robotic applications. To date, robots have been equipped with only a single, central artificial LGMD sensor, and this triggers a non-directional stop or rotation when a potentially colliding object is detected. Clearly, for a robot to behave autonomously, it must react differently to stimuli approaching from different directions. In this study, we implement a bilateral pair of LGMD models in Khepera robots equipped with normal and panoramic cameras. We integrate the responses of these LGMD models using methodologies inspired by research on escape direction control in cockroaches. Using ‘randomised winner-take-all’ or ‘steering wheel’ algorithms for LGMD model integration, the khepera robots could escape an approaching threat in real time and with a similar distribution of escape directions as real locusts. We also found that by optimising these algorithms, we could use them to integrate the left and right DCMD responses of real jumping locusts offline and reproduce the actual escape directions that the locusts took in a particular trial. Our results significantly advance the development of an artificial collision detection and evasion system based on the locust LGMD by allowing it reactive control over robot behaviour. The success of this approach may also indicate some important areas to be pursued in future biological research

Acceptability of a proposed practice pharmacist-led review for opioid-treated patients with persistent pain: A qualitative study to inform intervention development

Introduction Regular review of patients prescribed opioids for persistent non-cancer pain (PCNP) is recommended but not routinely undertaken. The PROMPPT (Proactive clinical Review of patients taking Opioid Medicines long-term for persistent Pain led by clinical Pharmacists in primary care Teams) research programme aims to develop and test a pharmacist-led pain review (PROMPPT) to reduce inappropriate opioid use for persistent pain in primary care. This study explored the acceptability of the proposed PROMPPT review to inform early intervention development. Methods Interviews ( n = 15) and an online discussion forum ( n = 31) with patients prescribed opioids for PCNP and interviews with pharmacists ( n = 13), explored acceptability of a proposed PROMPPT review. A prototype PROMPPT review was then tested and refined through 3 iterative cycles of in-practice testing (IPT) ( n = 3 practices, n = 3 practice pharmacists, n = 13 patients). Drawing on the Theoretical Framework of Acceptability (TFA), a framework was generated (including a priori TFA constructs) allowing for deductive and inductive thematic analysis to identify aspects of prospective and experienced acceptability. Results Patients felt uncertain about practice pharmacists delivering the proposed PROMPPT review leading to development of content for the invitation letter for IPT (introducing the pharmacist and outlining the aim of the review). After IPT, patients felt that pharmacists were suited to the role as they were knowledgeable and qualified. Pharmacists felt that the proposed reviews would be challenging. Although challenges were experienced during delivery of PROMPPT reviews, pharmacists found that they became easier to deliver with time, practise and experience. Recommendations for optimisations after IPT included development of the training to include examples of challenging consultations. Conclusions Uptake of new healthcare interventions is influenced by perceptions of acceptability. Exploring prospective and experienced acceptability at multiple time points during early intervention development, led to mini-optimisations of the prototype PROMPPT review ahead of a non-randomised feasibility study

Tactile learning by a whip spider, \u3ci\u3ePhrynus marginemaculatus\u3c/i\u3e C. L. Koch (Arachnida, Amblypygi)

The ability of animals to learn and remember underpins many behavioral actions and can be crucial for survival in certain contexts, for example in finding and recognizing a habitual refuge. The sensory cues that an animal learns in such situations are to an extent determined by its own sensory specializations. Whip spiders (Arachnida, Amblypygi) are nocturnal and possess uniquely specialized sensory systems that include elongated “antenniform” forelegs specialized for use as chemo- and mechanosensory feelers. We tested the tactile learning abilities of the whip spider Phrynus marginemaculatus in a maze learning task with two tactile cues of different texture—one associated with an accessible refuge, and the other with an inaccessible refuge. Over ten training trials, whip spiders got faster and more accurate at finding the accessible refuge. During a subsequent test trial where both refuges were inaccessible, whip spiders searched for significantly longer at the tactile cue previously associated with the accessible refuge. Using high-speed cinematography, we describe three distinct antenniform leg movements used by whip spiders during tactile examination. We discuss the potential importance of tactile learning in whip spider behavior and a possible role for their unique giant sensory neurons in accessing tactile information

Supplementary Material: Agonistic signals received by an arthropod filiform hair allude to the prevalence of near-field sound communication

SUPPLEMENTARY METHODS (i) Analysis of behaviour (ii) Stimulator design SUPPLEMENTARY RESULTS (i) Typical contest behaviour (ii) Additional data on ALV positioning relative to the receiver (iii) Electrophysiological control experiments (iv) Analysis of phase-locking SUPPLEMENTARY REFERENCES Includes 3 figures and 1 table

Prey capture by the whip spider \u3ci\u3ePhrynus marginemaculatus\u3c/i\u3e C.L. Koch

Whip spiders (Arachnida, Amblypygi) are little-studied arachnids with enlarged spiny pedipalps and elongated ‘‘antenniform’’ forelegs. These antenniform legs contain at least seven giant sensory neurons with no known behavioral function. Here we use high-speed cinematography to describe the prey capture behavior of the whip spider Phrynus marginemaculatus C.L. Koch 1840, in order to examine how these giant neurons might be involved. When presented with a prey item (a cricket), a whip spider first accurately aims one of its antenniform legs in the prey’s direction. Next, the whip spider orients its body to the prey item and approaches, placing one antenniform leg tip on either side of the prey. The whip spider may remain relatively still in this position for some time, before opening its pedipalps in preparation for a strike and then rapidly swinging its antenniform legs away from the prey item and striking at it with its pedipalps. In common with previous studies, our results show that giant neuron activity is not necessary to trigger any of the stages of normal prey capture behavior, but they also suggest that these neurons could still provide information important in this context

RDS_BiolLett_Expt2

Data from experiment