Gerlinde Höbel

• Dr. rer. nat.
• Professor (Associate) at University of Wisconsin–Milwaukee

The mate choice behaviors of females can greatly affect patterns of reproductive success in males and influence the evolution of sexually selected male traits. Population-level estimates of display preferences may provide an accurate estimate of the strength and direction of selection by female choice if all females in the population show homogeneo...

Semiaquatic animals breed in environments with a mix of aquatic and terrestrial features, each requiring appropriate types of locomotion with differential energetic demands and containing different suits of predators. We surveyed calling locations of male Eastern Gray Treefrogs ( Hyla versicolor ) at our study pond to assess average composition of...

Anurans use different sensory modalities to communicate and interact socially, including acoustic, chemical, tactile, and visual signals. In a multimodal context, these sensory modes can transmit different information to the receiver or even reinforce the same message. In this study, we hypothesized that body colour traits and vocal sac movements o...

Anuran communication is largely based on acoustic signals, but different sensory modes are also widespread, including visual communication using body color traits as a way of signaling. The Brazilian treefrog, Boana albomarginata, has a complex behavioral repertoire presenting several call types and performing gestures as visual signals. This speci...

Female mate choice decisions are guided by preferences for male display features, but in chorusing species the displays of different males may temporally overlap. Here, mate choice decisions may be guided by preferences based on signal timing in addition to signal features. Which type of preference dominates has implications for our understanding o...

Mate choice is an important cause of natural and sexual selection and drives the evolution and elaboration of male ornaments. Yet mate choice decisions are often neither consistent nor uniform, and a range of factors have been identified to influence variation between and within individuals. A potential source of variation influencing preferences a...

Recognizing form and function of animal defenses is paramount to understanding the ecological and evolutionary forces behind predator and prey dynamics. Color patterns are strongly related to defensive strategies in animals. Some rely on camouflage to avoid detection, while others are brightly colored and conspicuously signal their noxiousness to p...

The social environment is often the most dynamic and fitness-relevant environment animals experience. Here we tested whether plasticity arising from variation in social environments can promote signal-preference divergence-a key prediction of recent speciation theory but one that has proven difficult to test in natural systems. Interactions in mixe...

Animals that deter predatory attacks are at a selective advantage. Aposematism or the advertisement of bright colors that signals chemical defense is one of many methods animals employ to dispirit predation. Recognizing form and function of animal weaponry is paramount to understanding the ecological and evolutionary forces behind predator prey dyn...

Size‐assortative mating in frogs and toads should increase fitness, because pairs consisting of partners well matched for size should also have a higher proportion of fertilized eggs. We examined whether the size ratios of mated males and females had an effect on fertilization success in Eastern Gray Treefrogs and tested whether the naturally obser...

Mate choice is an important cause of natural and sexual selection, driving the evolution of ornaments and promoting diversification and speciation. Mate choice decisions arise from the interaction of several components, and knowledge of whether they interact, and how, is crucial for understanding their contributions to selection. Here we focus on t...

Sexual competition hinges on the ability to impress other conspecifics, to drive them away or attract them. In such cases, the selective environment may be hedonic or affective in nature, as it consists of the evaluations of the individuals making the decisions. This may contribute to the power of sexual selection because evaluations may range from...

Female mate choice is remarkably complex and has wide-ranging implications for the strength and direction of male trait evolution. Yet mating decisions can be fickle and inconsistent. Here, we explored predation risk as a source of variation in the effort a female is willing to invest in acquiring a preferred mate type (“choosiness”). We did so by...

Information on how organisms allocate resources to reproduction is critical for understanding population dynamics. We collected clutch size (fecundity) and egg size data of female Eastern Gray Treefrogs, Hyla versicolor , and examined whether observed patterns of resource allocation are best explained by expectations arising from life history theor...

Communal displays such as leks and choruses are puzzling phenomena, as it is not obvious why signalers or choosers should aggregate. It has been hypothesized that signalers in leks enjoy higher per capita reproductive success because choosers prefer to sample among dense configurations (“clusters”) that are easier to compare. While female preferenc...

Arthropod behaviour is usually explained through ‘hard-wired’ motor routines and learning abilities that have been favoured by natural selection. We describe observations in which two arthropods solved rare and perhaps completely novel problems, and consider four possible explanations for their behaviours: (i) the behaviour was a pre-programmed mot...

We explored the relationship between separate measures of female mate choice decisions in Eastern Gray Treefrogs. Our proposed hypothesis states that preference and choosiness are independent traits, predicting that (1) preference functions and choosiness will not be correlated with one another and (2) preference functions and choosiness will be in...

The dynamic nature of many breeding aggregations, where the composition and attractiveness of a male’s competitors are ever changing, places extreme pressure on advertising males to remain competitive. In response to this challenge, males may adjust the properties of their calls or change when they signal relative to their nearest neighbors, which...

To understand the efficacy of female choice in driving the evolution of male displays, we need to not only characterize preferences but examine the opportunity for the expression of such preferences. Mate assessment by females should be constrained if the relative attractiveness of multiple displays is perceived as equal because trait differences b...

Mate choice is an important cause of sexual selection; it can drive the evolution of extravagant ornaments and displays, and promote speciation through the reproductive isolation generated by rapid divergence of sexual traits. Understanding mate choice requires knowledge of the traits involved in generating mate-choice decisions, and how those trai...

Human activities are drastically changing the amount of artificial light entering natural habitats. Because light pollution alters the sensory environment, it may interfere with behaviors ranging from prey detection and vigilance to mate choice. Here, we test the hypothesis that anthropogenic light pollution affects the mate choice behavior of fema...

Animal signals are inherently complex phenotypes with many interacting parts combining to elicit responses from receivers. The pattern of interrelationships between signal components reflects the extent to which each component is expressed, and responds to selection, either in concert with or independently of others. Furthermore, many species have...

While the influence of environmental variables, particularly temperature and rainfall, on the breeding behavior of amphibians is widely recognized, relatively few studies have addressed how the moon affects amphibian behavior. Yet, the lunar cycle provides several rhythmic temporal cues that animals could use to time important group events such as...

Mate choice is an important driver of the evolution of sexual traits and can promote divergence and speciation. Understanding the underlying variation in mate choice decisions is crucial to understand variation in the strength and direction of sexual selection. We explored whether variation in the social environment influences mate choice decisions...

Nocturnal light levels vary throughout the course of the lunar cycle, being darkest during the new moon and brightest during the full moon. Many nocturnal animals change their behavior in response to this natural variation in moonlight intensity. Frequently, these behavioral changes can be attributed to the way in which moonlight affects the abilit...

Many organisms share communication channels, generating complex signaling environments that increase the risk of signal interference. Variation in abiotic conditions, such as temperature, may further exacerbate signal interference, particularly in ectotherms. We tested the effects of temperature on the pulse rate of male signals in a community of O...

Mate preferences are important causes of sexual selection. They shape the evolution of sexual ornaments and displays, sometimes maintaining genetic diversity and sometimes promoting speciation. Mate preferences can be challenging to study because they are expressed in animal brains, and because they are a function of the features of potential mates...

Anuran breeding activity is frequently linked to environmental factors, mainly temperature and rainfall. However, a key feature of anuran reproductive behavior—gathering in choruses and producing loud advertisement calls to attract females—generates a conspicuous social cue that may also facilitate reproductive behavior. Here, I examine the relativ...

Sensory receptors transmit information on multiple stimulus dimensions. Much remains to be understood about how the processing of different signal characteristics is partitioned and integrated in different areas of the nervous system. Amphibian hearing involves two morphologically distinct inner-ear organs that process different components of the f...

Perception is frequently cross-modal, involving interactions among stimuli in multiple sensory modalities. Cross-modal integration of sensory stimuli is well established in humans and laboratory mammals, but the understanding of its mechanisms and evolution is limited by a lack of data from a broader taxonomic range in an ecological framework. Our...

To decide efficiently where to forage, rest or breed, animals need information about their environment, which they may gather by monitoring the behavior of others. For example, attending to the signals of conspecifics or heterospecifics with similar habitat requirements may facilitate habitat choice. Such social information use seems taxonomically...

Among the factors that can influence female mate choice decisions is the degree to which females differentiate among similar displays: as differences decrease, females are expected to eventually stop discriminating. This discrimination threshold, in conjunction with the magnitude of male trait variation females regularly encounter while making mate...

Sexual selection takes place in complex environments where females evaluating male mating signals are confronted with stimuli from multiple sources and modalities. The pattern of expression of female preferences may be influenced by interactions between modalities, changing the shape of female preference functions, and thus ultimately altering the...

Nephila clavipes golden orb-web spiders accumulate prey larders on their webs and search for them if they are removed from their web. Spiders that lose larger larders (i.e., spiders that lose larders consisting of more prey items) search for longer intervals, indicating that the spiders form memories of the size of the prey larders they have accumu...

Competition for mates often occurs in social settings composed of many displaying males. While this poses some special challenges for communication, the proximity of other males may also provide information that chorus participants may use to adaptively adjust their calling behavior to the local level of competition. Conducting behavioral observati...

Many species gather in choruses to advertise and search for mates, creating noisy social environments that may impair effective communication. These challenges may be further compounded in mixed-species aggregations, where signals from different species overlap and mate-searching females may perceive heterospecific signals in more attractive relati...

We use allometric analysis to explore how acoustic signals scale on individual body size and to test hypotheses about the factors shaping relationships between signals and body size. Across case studies spanning birds, crickets, tree crickets, and tree frogs, we find that most signal traits had low coefficients of variation, shallow allometric scal...

Efficient foraging may be facilitated by attending to the signals produced by potential prey items. Such predatory eavesdropping is taxonomically widespread, yet there is currently a dearth of information for amphibians. Anuran amphibians, with their highly developed auditory system and robust phonotaxis toward advertisement calls when searching fo...

Nephila clavipes golden orb-web spiders accumulate prey larders on their webs and search for them if they are removed from their web. Spiders that lose larger larders (i.e., spiders that lose larders consisting of more prey items) search for longer intervals, indicating that the spiders form memories of the size of the prey larders they have accumu...

The visual ecology of nocturnal anurans is poorly understood but there is growing evidence that vision plays a role in important behaviors such as mate choice. While several recent studies demonstrated that females are responsive to visual cues when selecting mates, the forces responsible for these preferences are unknown. We investigated the respo...

During the mating season, male Gray treefrogs (Hyla versicolor) call to attract females. Although this behavior is crucial for mate attraction, it also makes them more susceptible to predation. To potentially minimize detection by predators, males could choose to call from sites in which they are best camouflaged. Therefore, we predicted that calli...

Calling behaviour is an essential component of gaining access to mates, and calling site selection may be an important component of effective communication. Environmental factors like microclimate, or the presence of competitors and predators often show seasonal or spatial variation, and behavioural plasticity that allows the caller to adjust to th...

The contribution of sexual selection to diversification remains poorly understood after decades of research. This may be in part because studies have focused predominantly on the strength of sexual selection, which offers an incomplete view of selection regimes. By contrast, students of natural selection focus on environmental differences that help...

The ability to sense water surface waves has been described in only a few species, but across a wide taxonomic range. Water surface waves are typically used to localize prey or to avoid predators, and in some cases also for sexual communication. Here we add to the sparse knowledge of the use of this sensory modality by reporting observational and e...

Nephila clavipes spiders accumulate prey larders on their webs. We conducted a field experiment to ask if the spiders search for larders that have been pilfered (experimentally mimicking the potential effect of kleptoparasites), and to ask if the spiders vary their search efforts according to the size of the larder. All spiders searched for larders...

Despite the importance of perceptually separating signals from background noise, we still know little about how nonhuman animals solve this problem. Dip listening, an ability to catch meaningful 'acoustic glimpses' of a target signal when fluctuating background noise levels momentarily drop, constitutes one possible solution. Amplitude-modulated no...

Substrate-borne vibrational communication is a common form of communication in animals. Current contact-based playback methods limit the number of substrates that can be stimulated simultaneously and potentially change the transmission properties of the substrate. Here, we explore a solution to these limitations by broadcasting airborne stimuli ont...

Mate choice often takes place in group settings, such as leks or choruses, in which numerous individuals display and compete for mates simultaneously. In addition to well-known preferences for male traits like size and signaling rate, females of group-displaying species often show preferences that are based on the relative timing of male signals, g...

Females often choose their mates based on features of the male’s advertisement signal, often preferring louder, deeper, longer, or faster signals. Females of chorusing animals also frequently have preferences for signal timing positions, generally preferring the leading signal. Under natural chorus conditions, females must choose among signals that...

Despite its small size, Costa Rica is blessed with a diverse fauna and flora. An important, albeit often overlooked, portion of this biodiversity is the herpeto-fauna, which includes the amphibians and reptiles. The high herpetological diversity is based in part on the ge-ographic location between North and South America, which allowed faunal eleme...

Tettigoniids use hearing for mate finding and the avoidance of predators (mainly bats). Using intracellular recordings, we studied the response properties of auditory receptor cells of Neoconocephalus bivocatus to different sound frequencies, with a special focus on the frequency ranges representative of male calls and bat cries. We found several r...

Signal-timing adjustment is common in communally signaling species, and there is large variation in signal-timing formats found in nature. We conducted a survey of geographic variation in female signal-timing preferences and male signaling behavior of a tree frog to test predictions of two hypotheses about the sources of selection acting on signal-...

In this paper, we compare the advertisement calls of 207 neotropical strawberry poison frogs (Dendrobates pumilio) collected in 21 localities along a transect from northern Costa Rica to western Panama. Populations varied most in call duration and call rate, while pulse rate and duty cycle were less variable. Multivariate analyses showed that call...

We studied the advertisement signals in two clades of North American hylid frogs in order to characterize the relationships between signal acoustic structure and underlying behavior. A mismatch was found between the acoustic structure and the mechanism of sound production. Two separate sets of phylogenetic characters were coded following acoustic v...

Advertisement calls of green treefrogs (Hyla cinerea) have two spectral peaks centered at about 1 kHz and 3 kHz. Addition of a component of intermediate frequency (1.8 kHz) to a synthetic call reduced its attractiveness to females relative to an alternative lacking this component. This mid-frequency suppression occurred over a 20-dB range of playba...

Interactions between species can affect the evolution of their sexual signals, receiver selectivity, or both. One commonly expected outcome is reproductive character displacement, whereby adverse consequences of mismating select for greater differentiation of communication systems in areas of sympatry than in areas of allopatry. We found evidence o...

The egg-laying basins and basin dynamics of the gladiator frog Hyla rosenbergi were studied in southeastern Costa Rica from May to August 1995. The majority of basins with calling males inside were water-filled puddles or cattle footprints; only 29% of the basins were male-constructed nests. Basin occupation time was generally short, lasting on ave...

Eleutherodactylus fitzingeri were studied during the dry and rainy seasons at an Atlantic lowland rainforest in Costa Rica. The frogs had one of three dorsal colour patterns (mottled, striped, uniform) and one of two ventral colour patterns (white, yellow). Males had significantly more often a yellow venter than females. Juveniles with a white bell...