Harmless Control Research Articles

Calling owl: Rails adjust vocal activity rates in response to changes in predation risk

Animal communication carries the risk of signal exploitation by predators, and thus many prey species will adjust their signals into more discreet messages to conspecifics, or conspicuous antipredator cues. Although rails (Family Rallidae) use the visual display of tail flicking as a warning of vigilance toward predators, how these birds alter their vocal behavior based on perceived predation risk remains little studied. The calls of owls, predatory birds that consume a variety of rallid species and can home in on acoustic cues of their prey, can reduce singing in numerous bird species. We applied remotely activated broadcasts and autonomous recording units to study whether rails in the wetlands of the Lake Calumet region near Chicago, Illinois, would decrease their vocal activity rate following the broadcast of a rallid predator, the Great Horned Owl (Bubo virginianus). Contrary to predictions, Soras (Porzana carolina) significantly increased vocal activity when exposed to owl vocalizations and decreased vocal activity when exposed to a harmless control. Our results indicate that rails appear to increase their vocal activity as a potential alarm mechanism, likely to reduce predation risk by warning conspecifics.

Untrained birds\u2019 ability to recognise predators with changed body size and colouration in a field experiment

BackgroundDuring recognition process, multiple parameters of the encountered stimulus may play a role. Previous studies with wild birds identified the importance of several salient features (e.g., eyes, beak, prominent elements of colouration) which birds use to recognise other bird species, such as predators or nest parasites. In the present study, we observed the responses of passerines visiting winter feeders to stimuli in the form of dummies of Eurasian sparrowhawk which were modified in body size and/or colouration but always carried the salient features of raptors (hooked beak, talons) and one species-specific feature of the sparrowhawk (yellow eyes). In the vicinity of a feeder, we placed a dummy of an unmodified sparrowhawk, life-sized sparrowhawk with pigeon, great tit, or robin colouration, a small, great tit-sized sparrowhawk dummy with unmodified or pigeon colouration, or an unmodified pigeon dummy, which functioned as a harmless control. Then we measured how it affected the number of visits.ResultsWe found that birds were less afraid of small dummies regardless of their colouration than they were of life-sized raptor dummies or even the pigeon dummy. This contrasts with the results of a previous laboratory experiment where great tits’ reaction to small dummies was comparably fearful to their response to life-size dummies. In our experiment, birds were also not afraid of life-sized dummies with modified colouration except for a robin-coloured dummy, which caused an equally significant fear reaction as an unmodified sparrowhawk dummy. It is likely that this dummy resembled the colouration of a male sparrowhawk closely enough to cause this effect.ConclusionsBased on our observations, we conclude that birds use contextual features to evaluate the size of other birds. Distance and familiar reference points seem to play an important part in this process.

An Experimental Test of Defenses Against Avian Brood Parasitism in a Recent Host

Theoretical studies predict that hosts of avian brood parasites should evolve defenses against parasitism in a matter of decades. However, opportunities to test these predictions are limited because brood parasites rarely switch to naïve hosts. Here, we capitalize on a recent host switch by the brood-parasitic Pacific Koel (Eudynamys orientalis) in eastern Australia, to investigate how quickly the Red Wattlebird (Anthochaera carunculata), a recent host that has been annexed by the koel within the last 90 years, can learn to recognize and mob adult cuckoos and evolve the ability to eject parasite eggs. Pacific Koel nestlings kill all host young, so there should be strong selection for hosts to evolve defenses. However, low parasitism rates and high egg recognition costs might slow the spread of egg ejection in our study populations, while adult parasite recognition should be able to spread more rapidly, as this defense has been shown to be a learned trait rather than a genetically inherited defense. We tested Red Wattlebirds at two sites where parasitism rate differed. As predicted, we found that the Red Wattlebird showed little or no ability to eject foreign model eggs at either site, whereas two historical hosts showed high levels of egg ejection at both sites. However, Red Wattlebirds responded significantly more aggressively to a koel mount than to mounts of a harmless control and nest predator at the site with the higher parasitism rate and gave significantly more alarm calls overall toward the koel mount. Our results support previous evidence that recognition and mobbing of a brood parasite are learned traits and may be especially beneficial to naïve hosts that have not had enough time or a high enough selection pressure to evolve egg rejection.

Dengue control measures via cytoplasmic incompatibility and modern programming tools

The vector borne diseases share a high percentage of the annual deaths reported by the world health organization. Due to the involvement of multiple factors and resistance of the vector to the treatment strategies, it is highly desired to design a safe, efficient and harmless control strategy. A state of the art computational framework for the Wolbachia induced “genetic-control-strategy” has been documented during this research. The process of mating and molecular identification is complex and expensive and different labs around the world are devoted to format a smooth implementation strategy of this approach. During this research, as a first step, data was collected, secondly, dynamic artificial neural networks, with the “tapped delay” lines are used for nonlinear filtering of the data and for the prediction of the parametric values of the novel mathematical model. To study parametric reliance of stable solutions and unstable solution we analyze stability and the corresponding thresholds desired for this study are documented. The study conducted during this research can prove to be useful in future experimental and theoretical studies, aimed to control the vector borne diseases.

Implicit evaluations of moral agents reflect intent and outcome

Explicit (directly measured) evaluations of moral agents reflect both the externally observable consequences of actions and inferences about the agent's hidden mental states: Negative outcomes without negative intent (e.g., someone getting killed accidentally) and negative intent without a negative outcome (e.g., a failed attempt to kill someone) are each sufficient for negative explicit evaluations of a moral agent to emerge. Across two studies (final N = 826; Study 2 preregistered), we newly investigated implicit (indirectly measured) evaluations of moral agents, as assessed by an Implicit Association Test (IAT). Study 1 included 3 between-participant conditions: accident (negative outcome + positive intent), attempt (positive outcome + negative intent), and harm (negative outcome + negative intent), each compared to a harmless (positive outcome + positive intent) control. Study 2 had a 2-by-2 design, in which outcome (positive vs. negative) and intent (positive vs. negative) were manipulated orthogonally, with targets in each condition compared to a neutral control whose actions did not carry moral implications. Mirroring prior findings obtained using explicit measures, implicit evaluations of moral agents tracked both manifest outcomes (e.g., someone falling from a bridge) and inferences about latent mental states (e.g., the intent to let someone fall off a bridge) in both paradigms. These results are difficult to reconcile with dual-process theories positing that implicit evaluations arise from low-level associative learning but they are readily accounted for by propositional theories according to which implicit evaluations are sensitive to high-level inferential reasoning.

Specific responses of cuckoo hosts to different alarm signals according to breeding stage: a test of the offspring value hypothesis.

The selective pressure exerted by avian brood parasites forces their hosts to evolve specific defense strategies. When subject to brood parasite attack, avian hosts will often emit alarm calls. To date, few studies have examined whether and how host responses to different alarm calls indicative of different enemies vary with the host’s breeding stage. We carried out alarm call playback experiments during both the egg and nestling stages of the oriental reed warbler Acrocephalus orientalis, a host of the common cuckoo Cuculus canorus. The playback exemplars were selected from recorded alarm calls of the warbler to the presence of common cuckoos, sparrowhawks Accipiter nisus, and oriental turtle doves Streptopelia orientalis, which represented brood parasite, predator, and harmless control, respectively. The results showed that the oriental reed warblers did not discriminate alarm calls issued to different intruder types, but the intensity of the response was significantly higher in the nestling stage than in the egg stage. Attack behavior related to sparrowhawk alarm calls was absent in the egg stage, but aggressive behavior increased dramatically and exceeded the attack frequency in response to the cuckoo alarm call in the nestling stage, implying a shift in the tradeoff between the parents’ own survival and the loss of offspring. Alarm calls attracted a larger number of conspecifics than members of other species. In general, the oriental reed warbler had consistently stronger responses to different alarm calls in the nestling stage than in the egg stage, supporting the offspring value hypothesis.

"Bottom-Up" Strategy for the Identification of Novel Soybean Peptides with Angiotensin-Converting Enzyme Inhibitory Activity.

IAVPTGVA (Soy1) and LPYP are two soybean peptides, which display a multifunctional behavior, showing in vitro hypocholesterolemic and hypoglycemic activities. A preliminary screening of their structures using BIOPEP suggested that they might be potential angiotensin-converting enzyme (ACE) inhibitors. Therefore, a bottom-up-aided approach was developed in order to clarify the in vitro hypotensive activity. Soy1 and LPYP dropped the intestinal and renal ACE enzyme activity with IC50 values equal to 14.7 ± 0.28 and 5.0 ± 0.28 μM (Caco-2 cells), and 6.0 ± 0.35 and 6.8 ± 0.20 μM (HK-2 cells), respectively. In parallel, a molecular modeling study suggested their capability to act as competitive inhibitors of this enzyme. Finally, in order to increase both their stability and hypotensive properties, a suitable strategy for the harmless control of their release from a nanomaterial was developed through their encapsulation into the RADA16-assembling peptide.

Object categorization by wild-ranging birds in nest defence

Despite object categorization being an important ability for the survival of wild animals, the principles behind this ability have been only scarcely studied using wild-ranging, untrained animals. Reiterating our previous study undertaken with wild-ranging titmice on winter feeders (Nováková et al. Behav Process 143:7-12, 2017), we aimed to test two hypotheses of object recognition proposed by animal psychology studies: the particulate feature theory and recognition by components in the methodological paradigm of nest defence. We tested whether the parents of the red-backed shrike (Lanius collurio) recognize the dummies of the common kestrel (Falco tinnunculus), which is a potential predator of large chicks or fledglings, as a threat in case when their body parts are scrambled. The kestrel dummy was presented with the head at the top, in the middle, and at the bottom of the body. We showed that the shrikes did not consider dummies of a kestrel with an inappropriately placed head as a threat to the nest and attacked it equally scarcely as the harmless control. These results support the theory of recognition by components, presuming that the mutual position of body parts is essential for appropriate recognition of the object. When the body parts were scrambled, most of shrikes were not able to identify the kestrel in such an object despite all local features (eye, beak, colouration, and claws) being present. Nevertheless, shrikes did not consider the scrambled dummies as completely harmless, because they fed their chicks in their presence significantly less often than in the presence of harmless control.

Differently sized cuckoos pose different threats to hosts.

Hole-nesting tits Parus spp. have been classified as “unsuitable” hosts for cuckoo parasitism because cuckoos cannot enter a cavity if the entrance is too small. However, Chinese tits could reject alien eggs and egg ejection rate increased with the local diversity of parasitic cuckoo species. Antiparasitic behavior among Chinese tits may have evolved due to greater size variation among sympatric cuckoo species. This raises the question of whether differently sized parasitic cuckoos pose different threats to Chinese tits. A green-backed tit Parus monticolus population that is sympatric with Asian emerald cuckoo Chrysococcyx maculatus (eme-cuckoo, small-sized parasite) and common cuckoo Cuculus canorus (com-cuckoo, large-sized parasite), and a cinereous tit P. cinereus population that is only sympatric with com-cuckoo were chosen as study organisms. We observed behavioral response and recorded alarm calls of the 2 tit species to eme-cuckoo, com-cuckoo, chipmunk Tamias sibiricus (a nest predator) and dove Streptopelia orientalis (a harmless control), and subsequently played back alarm calls to conspecific incubating females. In dummy experiments, both tit species performed intense response behavior to chipmunk, but rarely responded strongly to the 3 avian species. In playback experiments, both tit species responded strongly to conspecific chipmunk alarm calls, but rarely responded to dove alarm calls. The intensity of response of incubating female green-backed tits to eme-cuckoo and com-cuckoo alarm calls were similar to that of chipmunk alarm calls, while the intensity to eme-cuckoo alarm calls was higher than the intensity to dove alarm calls which was similar to that of com-cuckoo alarm calls. In contrast, few female cinereous tits responded to eme-cuckoo and com-cuckoo alarm calls. These findings indicated that the threat level of eme-cuckoo was slightly greater than that of com-cuckoo for sympatric green-backed tits, but not for allopatric cinereous tits.

Alarm call‐based discrimination between common cuckoo and Eurasian sparrowhawk in a Chinese population of great tits

AbstractMorphological resemblance of the common cuckoo Cuculus canorus to the Eurasian sparrowhawk Accipiter nisus has been regarded as an example of predator mimicry. Common hosts could distinguish parasites as the result of coevolution, while rare hosts or non‐hosts may mistake cuckoos for hawks because rare hosts or non‐hosts behave similarly when faced with these two species. Birds usually produce alarm calls in addition to showing behavioral responses when in danger. However, previous studies of identification by rare hosts or non‐hosts of sparrowhawks usually lacked experimental evidence of alarm calls. Great tits Parus major, a rare cuckoo host, perform similar behaviors and usually produce alarm calls in response to sparrowhawks and common cuckoos. Here, we tested whether great tits could distinguish common cuckoo from sparrowhawk based on analysis of their alarm calls and the effects of playback of alarm calls on conspecific behavior. Previous studies showed that great tits have a complex communication system that conveys information about predators, and they could perform different kinds of response behavior to different alarm calls. If great tits have not made the ability to distinguish between common cuckoo and sparrowhawk, then their acoustic responses to these two species and their response behaviors in playback experiments should be similar. Specimens of a common cuckoo (parasite), a sparrowhawk (predator) and an Oriental turtle dove Streptopelia orientalis (harmless control) were used to elicit and subsequently record the response behavior and alarm calls of great tits. There was no significant difference in behavioral response among great tits when exposed to the dummy of cuckoo, sparrowhawk and dove. In contrast, they differed significantly in alarm calls. Great tits produced more notes per call that contained increasing D‐type and decreasing I‐type notes when responding to sparrowhawk as compared to cuckoo or dove. In playback experiments, we found that great tits responded more strongly to great tit hawk than to great tit cuckoo or great tit dove alarm calls. Our study suggests that great tits are able to distinguish sparrowhawks from common cuckoos and convey relevant information in alarm calls by adjusting the number and combinations of notes of a single call type.

Birds at the Winter Feeder do not Recognize an Artificially Coloured Predator

AbstractIt is supposed that coloration may affect the recognition of predators by prey species; nevertheless, the significance of the coloration and its particular components in the recognition process remains unknown. We presented dummies of the European sparrowhawk (Accipiter nisus) with changed body coloration, but with all other typical features preserved (body size and shape, beak, eyes, legs), to great tits (Parus major) and blue tits (Cyanistes caeruleus) visiting a winter feeder. A pigeon (Columba livia f. domestica) dummy was used as a harmless control. Neither tit species showed passive avoidance in the presence of a dummy with an artificial, violet‐white chequered coloration. They obviously did not consider such an object to be a predator despite the presence of the raptor beak, eyes and talons. Sparrowhawk dummies with the coloration completely changed (altered with those of a harmless European robin) or with the typical colour feature removed (barred pattern on the underparts) were considered to be as dangerous as the unmodified sparrowhawk. We discuss the possibility that the effect of salient raptor‐like features such as beak shape, eye coloration, and leg and talons shape overwhelmed the effect of body coloration in these cases. Birds visiting the feeder probably were able to generalize the vigilance towards the sparrowhawk to other realistically coloured dummies, but not to the non‐natural dummy.

The alarm call system of breeding Brown Thornbills (Acanthiza pusilla): self-defence or nest defence?

Many species produce alarm calls during predator encounters that are directed at either conspecifics or the predator. Although many studies have investigated alarm calls in foraging individuals, antipredator communication during reproduction is rarely studied. In birds, where nest predation is a key cause of reproductive failure, some species have evolved sophisticated alarm calls to inform nestlings of danger from nest predators. However, different predator species differ in their primary prey type (brood predators, predators of adults), and accordingly, birds could have evolved different alarm calls depending on who is in danger. We experimentally investigated parental antipredator communication in Brown Thornbills (Acanthiza pusilla), where more than 50 % of all nests are depredated. We presented breeding pairs the models of a brood predator, a predator of adult birds and a harmless control species. Parents gave two different alarm calls (short and intense tzzt calls), which were not predator-specific, but responded to the predator of adults with more alarm calls than for the brood predator. Parental alarm calls did not affect nestling begging levels, which were influenced only by parental feeding rate. Our results suggest that alarm calls of breeding Brown Thornbills are mainly used as a form of self-defence by the individuals of the breeding pair rather than being directed at the nestlings. This fits with the predictions of life-history theory that parents in long-lived species are more concerned about their own survival.

Secure and transparent network traffic replay, redirect, and relay in a dynamic malware analysis environment

ABSTRACTDynamic analysis is typically performed in a closed network environment to prevent the malware under analysis from attacking machines on the Internet. However, many of today's malwares require Internet connectivity to operate and to be thoroughly analyzed in a closed network environment. We propose a secure and transparent network environment that allows the malware in a dynamic analysis environment to have seemingly unrestricted Internet access in a secure manner. Our environment transparently dispatches malicious network traffic to compatible decoys while allowing harmless control traffic to have Internet access. We use 12 real‐world malware samples, which involve Internet connections, to evaluate the effectiveness of the proposed environment. The evaluation shows that the proposed environment can allow malware to exhibit more network activities than a closed network environment and can even outperform the baseline open network environment in some cases. In the meantime, Internet security is maintained by the dispatching of attack and propagation traffic to decoys inside the analysis environment. Copyright © 2013 John Wiley & Sons, Ltd.

The effectiveness of hawk mimicry in protecting cuckoos from aggressive hosts

The close resemblance between the common cuckoo, Cuculus canorus, and the Eurasian sparrowhawk, Accipiter nisus, is often viewed as Batesian mimicry evolved by the cuckoo in response to the aggression of its host. However, the effectiveness of such mimicry is poorly known. We examined cuckoo–hawk discrimination ability in the great reed warbler, Acrocephalus arundinaceus, a well-known and aggressive cuckoo host. We measured the responses of birds to three combinations of simultaneously presented taxidermic mounts of the cuckoo, sparrowhawk and turtle dove, as a harmless control, placed near their nests. Great reed warblers clearly discriminated the two enemies from the innocuous species. They always attacked cuckoos and sparrowhawks more often than turtle doves suggesting they considered both a danger to their broods. However, when we confronted the tested birds with the simultaneously presented mounts of these species, the parents attacked the cuckoo more frequently than the sparrowhawk. The results revealed that although great reed warblers attacked both cuckoo and sparrowhawk mounts near their nest, they were able to discriminate between them. This may suggest that if cuckoos had evolved the visual mimicry of a sparrowhawk to avoid host attacks, this mimicry may be unsuccessful not only because it is imperfect and hosts can learn to discriminate but also because of the generalized nest defence of more aggressive hosts.

Technological questions during the use ofXysticus kochiagainstFrankliniella occidentalisin greenhouse pepper

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is one of the most important pests of greenhouse pepper in Hungary. It has a hidden lifestyle, a short generation interval and a high reproductive rate. Due to these characteristics it is difficult to obtain an effective, environment-friendly and harmless control of the pest. Previous studies have shown that under caged plant conditions, the common crab spider, Xysticus kochi (Thorell) (Araneae: Thomisidae) is effective against western flower thrips. In this study, we examined some of the technological questions of the use of spider larvae.We investigated the necessary amount and number of applications of spider larvae under caged plant conditions. The efficiency of spiders at the whole greenhouse level was also studied. While the ratio of damaged surface of peppers treated with X . kochi was significantly lower than that of non-treated plants, increasing the amount of spider larvae did not improve the effectiveness of ...

Reed warblers discriminate cuckoos from sparrowhawks with graded alarm signals that attract mates and neighbours

Brood parasites and predators pose unique threats that may favour the evolution of enemy-specific defence strategies. We considered whether reed warblers, Acrocephalus scirpaceus, have a specific alarm call for common cuckoos, Cuculus canorus, and whether their alarms attract mates and neighbours. Mounts of cuckoos (threat to nest but harmless to adults) were significantly more likely to be mobbed and were mobbed more strongly, with rasp calls and mandible snaps, than mounts of sparrowhawks, Accipiter nisus (threat to adults only), or teal, Anas crecca (a harmless control). However, calls were not acoustically specific to the kind of enemy presented, but rather varied in usage with mount distance from the nest and mount species. This suggests that reed warbler alarm signals are not functionally referential, but rather convey immediacy of threat to the nest. Mates and neighbours often approached during calling, and playback experiments confirmed they were more likely to be attracted by mobbing calls than by control calls. The response was graded, with higher repetition rates of mobbing calls attracting more individuals. Nevertheless, it is unlikely that mobbing calls functioned solely to attract mates and neighbours because calling continued even after these were attracted and was not more likely when there were close neighbouring nests, and attracted neighbours were sometimes chased away by residents. Our results show that reed warblers discriminate a brood parasite from both a dangerous species and an innocuous species by using graded alarm signals that attract conspecifics. This is compatible with the idea that nest defence by reed warblers includes a specific evolved response to brood parasitism.

A drug is effective if better than a harmless control

Valid trials can still be held, as with HIVNET 012, when ethics rules out a placebo group.

In vitro tolerability of human nasal mucosa: histopathological and scanning electron-microscopic evaluation of nasal forms containing Sandostatin®

An in vitro human nasal model was developed as a tool to study the local tolerability of nasal powder forms using excised nasal mucosa in a diffusion chamber. The suitability of this model was tested using Sandostatin (SMS) an octapeptide analog of somatostatin, as a reference drug enhanced by Avicel (microcrystalline cellulose) or lactose (100 mesh). The standard nasal spray vehicle was taken as a harmless control and 1% chenodeoxycholate (CDC) as a harmful control in terms of local tolerability. The extent of peptide permeation was determined by measuring SMS concentration in the receiving chamber. The labeling of SMS was detected by immunoperoxidase staining on cross sections. The local tolerability for all tested forms was assessed by histopathological examination and scanning electron microscopy. The apparent permeation coefficient allowed us to rank the absorption of the tested drug forms as Avicel > spray = lactose > 1%CDC. For all formulations, SMS was detected in the epithelium. No changes of the nasal mucosa could be observed with Avicel, lactose or nasal spray vehicle in the presence or absence of SMS. 1%CDC with or without drug showed an immediate destruction of the nasal epithelium. The validation of this in vitro model using human nasal mucosa will be further discussed as a tool for assessing the local tolerability of intranasally applied test substances.