Experimental Arena Research Articles

Larval Sea Lampreys (<i>Petromyzon marinus</i>) Do Not Emigrate from a Risky Habitat Under Semi-natural Conditions

Sea Lamprey (Petromyzon marinus), invaded the upper Great Lakes in the early 20th century, precipitating abrupt declines ina number of native fish species. A recently proposed alternative method for the behavioural manipulation of Sea Lamprey populations is the use of conspecific damage-released alarm and predator cues as potential repellents. We examined whether larval Sea Lamprey (Petromyzon marinus) ammocoetes can be manipulated to emigrate from an area by labeling their habitat “risky” with the regular release of chemosensory alarm cues over several days. in a semi-natural laboratory environment, we exposed eight replicate groups of eight ammocoetes twice a day, for 7 days, to deionized water (control), ammocoete whole-body extract (damage-released alarm cue), and 2-phenylethylamine HCl (predator cue). None of the experimental stimuli induced emigration from the experimental arena. This approach does not hold any promise for ammocoete behavioural manipulation in the context of a Sea Lamprey integrated management program.

Disentangling the visual cues used by a jumping spider to locate its microhabitat.

Many arthropod species have evolved to thrive only on the leaves of a particular species of plant, which they must be capable of finding in order to survive accidental displacement, developmental transitions or the changing of the seasons. A number of studies have tested whether such species select leaves to land or oviposit on based on their color, shape or size. Unfortunately, many studies did not control for correlates of these characters, such as the brightness of different colors, the areas of different shapes, and the level of ambient illumination in the vicinity of different sizes of leaves. In the present study, we tested for leaf color, shape and size preferences in a leaf-dwelling jumping spider (Lyssomanes viridis) with known summer and winter host plants, while controlling for these correlates. First, color preferences were tested outdoors under the natural illumination of their forest habitat. Lyssomanes viridis did not prefer to perch on a green substrate compared with various shades of gray, but did prefer the second darkest shade of gray we presented them with. Of the green and gray substrates, this shade of gray's integrated photon flux (350-700 nm), viewed from below, i.e. the spider's perspective in the arena, was the most similar to that of real leaves. This relationship also held when we weighted the transmitted photon flux by the jumping spiders' green photopigment spectral sensitivity. Spiders did not prefer the star-like leaf shape of their summer host plant, Liquidambar styraciflua, to a green circle of the same area. When given a choice between a L. styraciflua leaf-shaped stimulus that was half the area of an otherwise identical alternative, spiders preferred the larger stimulus. However, placing a neutral density filter over the side of the experimental arena with the smaller stimulus abolished this preference, with spiders then being more likely to choose the side of the arena with the smaller stimulus. In conclusion, L. viridis appears to use ambient illumination and possibly perceived leaf brightness but not leaf shape or color to locate its microhabitat. This calls for a careful re-examination of which visual cues a variety of arthropods are actually attending to when they search for their preferred host species or microhabitat.

The Trojan horse approach for managing invasive ants: a study with Asian needle ants, Pachycondyla chinensis

Ants are among the most ecologically and economically significant biological invaders and are notoriously difficult to eradicate once established. Invasive ants are typically managed with toxic baits which are often unattractive to the target species, toxic to non-targets, and environmentally persistent. The current study evaluated a novel Trojan horse approach for managing invasive ants in natural habitats based on the use of poisoned prey. Eastern subterranean termites (Reticulitermes flavipes) were topically exposed to fipronil and presented to Asian needle ants (Pachycondyla chinensis) which are a significant invader in natural and disturbed habitats in the eastern United States. In laboratory assays, P. chinensis colonies were offered fipronil-treated termites within experimental arenas. The termites were readily attacked and consumed and results demonstrate that a single termite exposed to 25 ppm fipronil for 1 h is capable of killing 100 P. chinensis workers in 9 h. To evaluate population effects, field studies were conducted in forested areas invaded by P. chinensis. Fipronil-treated termites scattered on the forest floor provided rapid control of P. chinensis and ant densities throughout the treated plots declined by 98 ± 5 % within 28 days. I demonstrate that the poison baiting approach based on fipronil-treated termite prey is highly effective against P. chinensis and may offer an effective alternative to traditional bait treatments against other invasive ants, especially those with predatory and generalist feeding habits. Furthermore, I demonstrate that the poison baiting approach offers environmental benefits by delivering substantially less toxicant to the environment relative to current control methods which rely on commercial bait formulations. In summary, the poison baiting approach evaluated in this study appears highly suitable for controlling invasive ants and should be further tested against other invasive ants.

Antipredator responses in Tetranychus urticae differ with predator specialization

AbstractThe behavioural response of Tetranychus urticae to chemical cues from specialist predatory mites, Phytoseiulus persimilis, or generalist predatory bugs, Orius majusculus, on either bean or strawberry was studied in experimental arenas. Predators were placed on the leaf disc for 24 h and removed before T. urticae females were introduced. After 24 h, prey fecundity (number of eggs laid) and dispersal (number of prey drowned in the water barrier) were assessed. Chemical cues from the specialist predator resulted in reduced prey fecundity, significantly different from the generalist predator and control treatments. No interaction effect was found between plant species and prey fecundity, while significantly more eggs were laid on bean than on strawberry. Predator cues irrespective of predator specialization resulted in more prey dispersal than in the control. Findings emphasize the importance of specialization in the predator species complex for the degree and type of antipredator responses and resulting biological control.

Spatio‐temporal analysis of the role of faecal depositions in aggregation behaviour of the triatomine Rhodnius prolixus

AbstractSeveral triatomine species aggregate over conspecific faeces. In some domestic species, this behaviour might help individuals to find their refuges because faeces are usually deposited around such places. In the present study, the defaecation behaviour of the triatomine bug Rhodnius prolixus Stål (Heteroptera: Reduviidae) is described in detail, including the temporal pattern of aggregation of nymphs with different nutritional status to faeces of different post‐deposition times. First, using an experimental arena, the spatial distribution of faecal deposition spots released by nymphs, in relation to the position of a refuge, is recorded. The results show that a high density of faeces is deposited inside the refuge, and few and distant spots, in relation to the position of the refuge, are dropped outside. Second, whether the aggregation behaviour of nymphs is altered by the time elapsed from deposition of the faeces, and by the nutritional status of the insects, is determined. The post‐deposition time of the faeces strongly modulates the aggregation response of the insects. Differences in aggregation between fed and unfed insects are only marginally significant; however, different temporal windows of aggregation according to the post‐deposition times of the faeces are demonstrated between bugs of different nutritional status. The results are discussed with respect to the relevance of the aggregation signal in relation to the characteristics of the natural refuges used by R. prolixus.

Collective behavior of soldier crab swarm in both ring- and round-shaped arenas

In study of collective behavior, though collective foraging behavior against surroundings is one of the most vivid examples about how animal group responses to external environment, relative experiment is rare. In this paper, we show an experiment with respect to collective foraging using a swarm of soldier crabs Mictyris guinotae, which live in the tideland and can form large swarms. We recorded the behaviors of soldier crab swarms with 10, 20, 30, 40 individuals in experimental arenas. Thanks to markers attached to crabs' shells and image-processing software, we obtained time series of individuals' position during 30 min. As a consequence, we found the soldier crabs form densely swarm to some extent in the ring-shaped experimental arena. Moreover, when we calculated the time between direction changes of the swarm, we found that it followed power-law distribution, containing very long moves. Such movement pattern is frequently found in foraging behavior of single animals. Our results, therefore, suggest that collective swarms show a type of foraging behavior as a single group.

Strengthening regional innovation through network-based innovation brokering

The primary objective of this paper is to demonstrate how regional innovation system theory may be translated into manageable micro-level methods with the potential for strengthening the productive dynamics of a regional innovation system. The paper meets this objective by presenting network-based innovation brokering (NBIB), a practical method designed using insights from regional innovation system theory and trust theory. Five cases from two Norwegian regional innovation networks show that in addition to knowledge development and diffusion, NBIB strengthened collaborative attitude and trust between members of the regional innovation system. Moreover, it served as an arena for entrepreneurial experimentation, resulting in projects combining two modes of innovation; the Science, Technology and Innovation mode and the Doing, Using and Interaction mode. The method, thus, may be viewed as a useful addition to the inventory of methods used to stimulate innovation in regional innovation systems (RISs). On a more general level, the paper represents a call to the community of innovation researchers and practitioners to give a higher priority to the question of how to better realize the pragmatic potential of RIS-theory.

Perceived prey quantity modulates oviposition in the ladybird Menochilus sexmaculatus

The ability of the ladybird Menochilus sexmaculatus (Fabricius) to modulate reproductive output in response to varying actual and perceived prey conditions was investigated using two prey species. An experimental arena was established by partitioning Petri dishes into two compartments using muslin cloth, the lower compartment being a perceived prey zone and the upper being the real prey zone. Ovipositing females were placed in the real prey zone with the minimal supply of aphid required for oviposition, while aphid quantity (abundant, scarce or absent) and aphid species were varied in the perceived zone. Females were found to respond to a perceived increased quantity of each prey species by increasing oviposition, even when the quantity of prey actually supplied was minimal. Perceived scarcity and absence of prey reduced oviposition, even when the female was actually consuming a similar quantity of prey to the perceived abundant condition. There was, however, no effect of perceived prey conditions on egg viability. The study thus revealed that this ladybird is able to perceive the presence of prey in its environment and modify its oviposition accordingly. It also demonstrates that it is the perception of prey that influences oviposition more than the actual prey consumed.

Aggression, mate guarding and fitness in male fruit flies

Aggression is a central trait affecting fitness, which has been well studied in many animals. As a part of a research programme integrating mechanisms and fitness consequences of aggression, we examined the adaptive functions of antagonistic interactions in fruit flies, Drosophila melanogaster, a species in which aggression has been studied primarily in the context of territorial behaviour. In our experiments, males at an attractive food patch were more aggressive towards other males when they were in the presence of their recent mates than when they were in the presence of females mated with other males. Furthermore, while recently mated males accompanied by their mates were more aggressive than virgin males, recently mated males and virgin males showed similar levels of aggression in the presence of females mated with other males. When we allowed focal males to mate inside experimental arenas and then added intruder males, the intruder males spent less time on the food patch, remated with the resident females at lower frequencies and fathered a smaller proportion of offspring when the focals males remained in the arenas than when we removed the focal males. Our results reveal a novel adaptive function of aggression in fruit flies: in addition to fighting to defend attractive food sources that attract prospective mates, males rely on aggression to guard their mates, and such mate guarding enhances their fitness.

Navigation-specific neural coding in the visual system of Drosophila

Drosophila melanogaster are a good system in which to understand the minimal requirements for widespread visually guided behaviours such as navigation, due to their small brains (adults possess only 100,000 neurons) and the availability of neurogenetic techniques which allow the identification of task-specific cell types. Recently published data describe the receptive fields for two classes of visually responsive neurons (R2 and R3/R4d ring neurons in the central complex) that are essential for visual tasks such as orientation memory for salient objects and simple pattern discriminations. What is interesting is that these cells have very large receptive fields and are very small in number, suggesting that each sub-population of cells might be a bottleneck in the processing of visual information for a specific behaviour, as each subset of cells effectively condenses information from approximately 3000 visual receptors in the eye, to fewer than 50 neurons in total. It has recently been shown how R1 ring neurons, which receive input from the same areas as the R2 and R3/R4d cells, are necessary for place learning in Drosophila. However, how R1 neurons enable place learning is unknown. By examining the information provided by different populations of hypothetical visual neurons in simulations of experimental arenas, we show that neurons with ring neuron-like receptive fields are sufficient for defining a location visually. In this way we provide a link between the type of information conveyed by ring neurons and the behaviour they support.

Does Angling Technique Selectively Target Fishes Based on Their Behavioural Type?

Recently, there has been growing recognition that fish harvesting practices can have important impacts on the phenotypic distributions and diversity of natural populations through a phenomenon known as fisheries-induced evolution. Here we experimentally show that two common recreational angling techniques (active crank baits versus passive soft plastics) differentially target wild largemouth bass (Micropterus salmoides) and rock bass (Ambloplites rupestris) based on variation in their behavioural tendencies. Fish were first angled in the wild using both techniques and then brought back to the laboratory and tested for individual-level differences in common estimates of personality (refuge emergence, flight-initiation-distance, latency-to-recapture and with a net, and general activity) in an in-lake experimental arena. We found that different angling techniques appear to selectively target these species based on their boldness (as characterized by refuge emergence, a standard measure of boldness in fishes) but not other assays of personality. We also observed that body size was independently a significant predictor of personality in both species, though this varied between traits and species. Our results suggest a context-dependency for vulnerability to capture relative to behaviour in these fish species. Ascertaining the selective pressures angling practices exert on natural populations is an important area of fisheries research with significant implications for ecology, evolution, and resource management.

Helpful invaders: Can cane toads reduce the parasite burdens of native frogs?

Many invading species have brought devastating parasites and diseases to their new homes, thereby imperiling native taxa. Potentially, though, invaders might have the opposite effect. If they take up parasites that otherwise would infect native taxa, but those parasites fail to develop in the invader, the introduced species might reduce parasite burdens of the native fauna. Similarly, earlier exposure to the other taxon's parasites might ‘prime’ an anuran's immune system such that it is then able to reject subsequent infection by its own parasite species. Field surveys suggest that lungworm counts in native Australian frogs decrease after the arrival of invasive cane toads (Rhinella marina), and laboratory studies confirm that native lungworm larvae enter, but do not survive in, the toads. In laboratory trials, we confirmed that the presence of anurans (either frogs or toads) in an experimental arena reduced uptake rates of lungworm larvae by anurans that were later added to the same arena. However, experimental exposure to lungworms from native frogs did not enhance a toad's ability to reject subsequent infection by its own lungworm species.

Low doses of the common alpha-cypermethrin insecticide affect behavioural thermoregulation of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae)

Sub-lethal effects of pesticides on behavioural endpoints are poorly investigated in non-targeted beneficial carabids. Conspicuous changes in locomotor activity of carabids exposed to sub-lethal doses of neurotoxic insecticides suggest that many other behaviours of these insects might be severely injured as well. We hypothesize that behavioural thermoregulation of carabids may be affected by low doses of neurotoxic pyrethroid insecticide alpha-cypermethrin which may have direct deleterious consequences for the fitness and populations of the beetles in the field. Automated video tracking of the carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) on an experimental thermal mosaic arena using EthoVision XT Version 9 software (Noldus Information Technology, Wageningen, The Netherlands) showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations (0.1–10mgL−1) drastically reduces the ability of the beetles for behavioural thermoregulation. At noxious high temperature, a considerable number of the beetles died due to thermo-shock. Other intoxicated beetles that survived exposure to high temperature displayed behavioural abnormalities. During heating of the arena from 25 to 45°C, insecticide treated beetles showed a significant fall in tendency to hide in a cool shelter (20°C) and prolonged exposure to noxious high temperatures, accompanied by changes in locomotor activity. Next day after insecticide treatment the beetles recovered from behavioural abnormalities to a large extent but they still were considerably longer exposed to noxious high temperatures compared to the negative control beetles. Our results demonstrated that behavioural thermoregulation is a sensitive and important etho-toxicological biomarker in ground-dwelling carabids. Prolonged exposure to unfavourably high temperatures has an array of negative effects decreasing fitness and survival of these insects at elevated thermal conditions with deep temperature gradients, typical of agricultural habitats. These results may have importance in IPM programs promoting reduced insecticide use.

Oviposition in the blood-sucking insect Rhodnius prolixus is modulated by host odors.

BackgroundTriatomine bugs are blood-sucking insects, vectors of Chagas disease. Despite their importance, their oviposition behavior has received relatively little attention. Some triatomines including Rhodnius prolixus stick their eggs to a substrate. It is known that mechanical cues stimulate oviposition in this species. However, it is not clear if chemical signals play a role in this behavior. We studied the role of host cues, including host odor, in the oviposition behavior of the triatomine R. prolixus.MethodsTests were carried out in an experimental arena and stimuli consisted of a mouse or hen feathers. The number of eggs laid and the position of those eggs with respect to the stimulus source were recorded. Data were analyzed using the Mann-Whitney and Kruskal-Wallis tests.ResultsBoth a mouse and hen feathers stimulated oviposition. In addition, hen feathers evoked a particular spatial distribution of eggs that was not observed in the case of mouse.ConclusionsWe propose that volatile chemical cues from the host play a role in the oviposition behavior of triatomines that stick their eggs. Thus, host odor would stimulate and spatially guide oviposition.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-0867-5) contains supplementary material, which is available to authorized users.

Variability in Small Hive Beetle (Coleoptera: Nitidulidae) Reproduction in Laboratory and Field Experiments.

Experiments were conducted to examine how several key factors affect population growth of the small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae). Laboratory experiments were conducted to examine effects of food quantity and temperature on reproduction of cohorts of young A. tumida adults (1:1 sex ratio) housed in experimental arenas. Daily numbers and total mass of larvae exiting arenas were highly variable within treatment. Either one or two cohorts of larvae were observed exiting the arenas. Food quantity, either 10 g or 20 g, did not significantly affect the number of larvae exiting arenas at 32°C, but did at 28°C; arenas provided 20 g food produced significantly more larvae than arenas provided 10 g. Temperature did not affect the total mass of larvae provided 10 g food, but did affect larval mass provided 20 g; beetles kept at 28°C produced more larval mass than at 32°C. Field experiments were conducted to examine A. tumida reproductive success in full strength bee colonies. Beetles were introduced into hives as egg-infested frames and as adults, and some bee colonies were artificially weakened through removal of sealed brood. Efforts were unsuccessful; no larvae were observed exiting from, or during the inspection of, any hives. Possible reasons for these results are discussed. The variability observed in A. tumida reproduction even in controlled laboratory conditions and the difficulty in causing beetle infestations in field experiments involving full colonies suggest that accurately forecasting the A. tumida severity in such colonies will be difficult.

Initiation and spread of escape waves within animal groups.

The exceptional reactivity of animal collectives to predatory attacks is thought to be owing to rapid, but local, transfer of information between group members. These groups turn together in unison and produce escape waves. However, it is not clear how escape waves are created from local interactions, nor is it understood how these patterns are shaped by natural selection. By startling schools of fish with a simulated attack in an experimental arena, we demonstrate that changes in the direction and speed by a small percentage of individuals that detect the danger initiate an escape wave. This escape wave consists of a densely packed band of individuals that causes other school members to change direction. In the majority of cases, this wave passes through the entire group. We use a simulation model to demonstrate that this mechanism can, through local interactions alone, produce arbitrarily large escape waves. In the model, when we set the group density to that seen in real fish schools, we find that the risk to the members at the edge of the group is roughly equal to the risk of those within the group. Our experiments and modelling results provide a plausible explanation for how escape waves propagate in nature without centralized control.

Risk-taking behaviours in zebra finches affected by mercury exposure

The trade-off between starvation and predation risk is of paramount importance to songbirds and many other small organisms. A contaminant with metabolic or neurological effects may hinder a bird's ability to manage these ecological risks, which are contingent on metabolic state and require cognitive assessments. Methylmercury (MeHg) is a ubiquitous pollutant that is associated with neurotoxicity, reproductive failure, altered behaviour and increased mortality in aquatic organisms. It was recently discovered that MeHg can enter terrestrial food webs and affect songbirds that eat contaminated invertebrates. Research on behavioural effects of environmentally relevant doses of MeHg in songbirds is a conservation priority as this pollutant is widespread, poorly regulated, increasing and understudied in terms of sublethal effects such as abnormal behaviours. To help close this knowledge gap, we examined how MeHg affects behavioural strategies in captive zebra finches, Taeniopygia guttata. We quantified the birds' responses to risk by measuring regulation of body mass, vigilance behaviour, willingness to move away from dense cover in search of food and reluctance to return to foraging after a disturbance. Dosed and undosed birds were placed in an experimental arena and were videorecorded over 3 days of increasing perception of predation risk. We found that MeHg-exposed birds, compared to control birds, (1) lost significantly more mass and (2) waited significantly longer to forage under the highest predation risk. Our results indicate that MeHg-exposed birds may react more strongly to threat of predation and thereby increase their risk of starvation. To our knowledge this is the first mechanistic study of how a pervasive pollutant may alter optimal decision making, and therefore potentially survival, in songbirds.

Predators, host abundance, and host spatial distribution affect the movement of wingless non-colonizing vector Rhopalosiphum padi (L.) and PVY prevalence in an oat/potato system

In the study of insect-vectored plant viruses, colonizing vector species remain the focus. However, non-colonizing vector species, those that do not settle and reproduce on the viral plant host, are often the most abundant in the field and may be the largest contributors to disease spread. While non-colonists may have a substantial effect on disease prevalence, the factors influencing their movement and transmission on non-host plants have been little studied. Here we evaluated how a common biological control agent (Hippodamia convergens), host and non-host plant abundance, and plant spatial distribution impact the movement and density of a wingless non-colonizing vector [Rhopalosiphum padi (L.)] and transmission of potato virus Y (PVY) in potatoes in experimental arenas. The results of this work illustrate the importance of plant species function (host or non-host) and distribution to vector behavior and disease spread. Predation, host plant abundance, and plant spatial distribution interactively affected viral prevalence within infected arenas. Increasing the number of vector non-host plants increased the distance and frequency of aphid movement, and the effect was influenced by plant spatial distribution, the arrangement of plant species in the experimental arena. Increasing the number of vector host plants increased the density of aphids. Although the interaction of the plant and predator treatments affected the proportion of potato plants infected in arenas where infection occurred, and host abundance and spatial distribution impacted vector movement and viral prevalence, aphid movement did not appear to mediate the effect of plant and predator treatments on PVY prevalence. This work demonstrates that both wingless non-colonizing vector behavior and transmission are aggregated responses to multiple environmental drivers.

Bioconcentration of phenanthrene and metabolites in bile and behavioral alterations in the tropical estuarine guppy Poecilia vivipara

Quantification of polycyclic aromatic hydrocarbon (PAH) metabolites in fish bile is widely used to evaluate levels of internal PAH contamination in fish, whereas behavioral effects are deemed important to address potential risks to fish populations. The estuarine guppy Poecilia vivipara was exposed for 96h to waterborne phenanthrene at concentrations of 10, 50, 200 and 500μgL−1. Phenanthrene and metabolites in bile were analyzed by fixed fluorescence at 260/380nm (excitation/emission) wavelengths. Phenanthrene increased in the bile of exposed fish in a dose-dependent pattern, and log bile bioconcentration factors ranged from 4.3 to 3.9 at 10 and 500μgL−1 phenanthrene, respectively, values that are similar to predicted bioconcentration factors based on phenanthrene Kow. Swimming resistance index was reduced to 81% of control values at 500μgL−1. Alteration of swimming speed was non monotonic, with a significant speed increase relative to control fish in treatments 50 and 200μgL−1 phenanthrene, respectively, followed by a speed decrease in fish exposed to 500μgL−1. However, swimming trajectories of fish exposed to 50, 200 and 500μgL−1 was altered by the development of a repetitive circular swimming behavior, in contrast to the controls that explored the entire experimental arena. This change in swimming patterns apparently explains the reduction in prey capture rates at 200μgL−1 phenanthrene. This study provides important information enabling the use of the estuarine guppy P. vivipara to monitor PAH metabolites in bile and its bioconcentration, linking internal exposure with ecologically relevant behavioral effects in the species.

Southern toads alter their behavior in response to red-imported fire ants

We used the southern toad (Anaxyrus terrestris) as a model species to explore how an invasive species, the red-imported fire ant (Solenopsis invicta; hereafter RIFA), influences amphibian predator avoidance and movement behaviors. Our objective was to determine if toads spent less time near and moved more frequently in the presence of RIFAs compared to pyramid ants by comparing behavioral reactions of toads to RIFAs versus a control and pyramid ants versus a control. Laboratory experiments involved three treatments including no ants, RIFAs, and native pyramid ants (Dorymyrmex bureni) within an experimental arena. We randomly placed ants into one of two containers located at each end of the arena. For each trial we placed a toad into the experimental arena, allowed the toad to acclimate and then recorded its behavior. We calculated the proportion of time the toad spent near ants and the number of movements completed by each toad. Comparing the RIFA treatment to the pyramid ant treatment, toads spent 35 % less time on the half of the experimental arena near RIFAs (P = 0.0304). Toad movements were 1.5 times more frequent in trials with RIFAs than pyramid ants (P = 0.0488). We propose that southern toads associate RIFAs either with increased predation risk or risk of injury compared to pyramid ants. Although the behaviors we observed might lessen the direct effects of RIFAs on southern toads via predation and injury, the indirect effects of increased movement and avoidance of RIFAs could also influence toad fitness by decreasing reproductive and foraging success.