Discriminant function analysis with nonindependent data: consequences and an alternative

Mundry, Roger; Sommer, Christina

doi:10.1016/j.anbehav.2006.12.028

Cited by 288 publications

(242 citation statements)

References 31 publications

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“…Consequently, the actual strength of the individual vocal signature is probably somewhat lower than reported here. The strength of the sex-specific signature, however, is not statistically overestimated since we avoided pseudoreplication by using only mean values per individual (see [46] for details). Interestingly, our results indicated that female S. bilineata which are approximately 15 per cent larger than males [31] tended to call at higher frequencies with shorter call duration compared with males.…”

Section: Discussionmentioning

confidence: 99%

“…A cross-validation procedure was used to correctly assign echolocation call duplets to the respective individuals. We estimated the significance of the classification success by using a two-tailed binomial test (following [46]). In order to test for sex-and location-specific signatures in echolocation calls, we used two different statistical approaches.…”

Section: Methodsmentioning

confidence: 99%

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Bat echolocation calls facilitate social communication

et al. 2012

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Bat echolocation is primarily used for orientation and foraging but also holds great potential for social communication. The communicative function of echolocation calls is still largely unstudied, especially in the wild. Eavesdropping on vocal signatures encoding social information in echolocation calls has not, to our knowledge, been studied in free-living bats so far. We analysed echolocation calls of the polygynous bat Saccopteryx bilineata and found pronounced vocal signatures encoding sex and individual identity. We showed experimentally that free-living males discriminate approaching male and female conspecifics solely based on their echolocation calls. Males always produced aggressive vocalizations when hearing male echolocation calls and courtship vocalizations when hearing female echolocation calls; hence, they responded with complex social vocalizations in the appropriate social context. Our study demonstrates that social information encoded in bat echolocation calls plays a crucial and hitherto underestimated role for eavesdropping conspecifics and thus facilitates social communication in a highly mobile nocturnal mammal.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Bat echolocation calls facilitate social communication

et al. 2012

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“…In this procedure, each call is classified by the functions derived from all calls other than that one. Since the acoustic data for food-associated calls were two-factorial (caller ID; call type), it has been argued that conventional DFA does not allow for a valid estimation of the overall significance of discriminability (Mundry & Sommer 2007). Therefore, we used a permuted discriminant function analysis (pDFA), using a macro written by R. Mundry and C. Sommer (Mundry & Sommer 2007), to estimate the significance of the number of correctly classified calls (cross-validated).…”

Section: Acoustic Analysesmentioning

confidence: 99%

“…The success rate of classification of call types was highest for barks and peeps, followed by yelps and then peep-yelps (correct classification for barks ¼ 96%, peeps ¼ 94%, yelps ¼ 80%, peepyelps ¼ 74%). We then used a pDFA (Mundry & Sommer 2007) to estimate the significance of the number of correctly classified calls (cross-validated). Results from the pDFA indicated a highly significant level of discrimination (P ¼ 0.001).…”

Section: Acoustic Analysesmentioning

confidence: 99%

Food-associated calling sequences in bonobos

2009

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Keywords: bonobo call sequence food-associated call Pan paniscus primate vocal communication When encountering food, chimpanzees, Pan troglodytes, and some other primates produce specific calls, whose acoustic structure covaries with the caller's food preference. For chimpanzees, there is evidence that listeners use these contingencies to guide their own foraging behaviour. Here, we investigated the vocal behaviour of another great ape, the bonobo, Pan paniscus, in response to food. We were able to distinguish acoustically five different call types given during interactions with food. These calls were not given singly, but usually as part of long and complex call sequences. We established the food preference hierarchies for 10 different individuals, housed at two different facilities. We found that the composition of call sequences produced by these individuals was not random, but was related to the type of food encountered by the caller. Significant variation in call composition was explained by taking into account the caller's individual food preferences, suggesting that bonobo food-calling sequences convey meaningful information to other group members.Numerous mammals and birds produce calls in response to food and these signals commonly attract other group members (e.g.

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“…To test further whether acoustic structure could be assigned to the identity and cycle stage, we performed a discriminant function analysis (DFA). Because cycle stage was confounded by multiple contributions from the same female, we conducted a permutated discriminant function analysis (pDFA) using scripts provided by R. Mundry (Mundry and Sommer 2007). We performed colinearity checks for the 10 parameters and found that all had satisfactory variance inflation factors of <7.0 (Allison 1999;Slocombe and Zuberbühler 2007).…”

Section: Statistical Analysesmentioning

confidence: 99%

Copulation Calls in Female Chimpanzees (Pan troglodytes schweinfurthii) Convey Identity but Do Not Accurately Reflect Fertility

2011

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Copulation calls are a relatively common feature of female primate behavior thought to function in the advertisement of female receptivity and subsequent incitation of male-male competition. To date, the majority of work on copulation calling behavior has focused on various monkey species, with little empirical evidence from the great apes. Previous research on wild chimpanzees (Pan troglodytes schweinfurthii) has suggested that estrous females produce copulation calls to avoid monopolization by single males and to minimize competition from other females. We here extended these findings by investigating to what degree these social demands were reflected in the calls' acoustic structure. We recorded and acoustically analyzed 71 copulation call bouts from 6 adult female chimpanzees in the Budongo Forest, Uganda. We did not find any acoustic differences in calls given by females in fertile and nonfertile periods, as assessed by their hormonal profiles. However, the calls' acoustic structure did reliably encode identity cues of the calling female. We propose that, in chimpanzees, the use and morphology of copulation calls have jointly been shaped by the selective advantage of concealing fertility. Owing to the low visibility conditions associated with chimpanzees' natural forest habitat and their dispersed social system, providing identity cues may be of particular biological relevance for these nonhuman primates.

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Discriminant function analysis with nonindependent data: consequences and an alternative

Cited by 288 publications

References 31 publications

Bat echolocation calls facilitate social communication

Bat echolocation calls facilitate social communication

Food-associated calling sequences in bonobos

Copulation Calls in Female Chimpanzees (Pan troglodytes schweinfurthii) Convey Identity but Do Not Accurately Reflect Fertility

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