When Less Is Best: Female Brown-Headed Cowbirds Prefer Less Intense Male Displays

Sexual selection theory predicts that females should prefer males with the most intense courtship displays. However, wing-spread song displays that male brown-headed cowbirds (Molothrus ater) direct at females are generally less intense than versions of this display that are directed at other males. Because male-directed displays are used in aggressive signaling, we hypothesized that females should prefer lower intensity performances of this display. To test this hypothesis, we played audiovisual recordings showing the same males performing both high intensity male-directed and low intensity female-directed displays to females (N = 8) and recorded the females' copulation solicitation display (CSD) responses. All eight females responded strongly to both categories of playbacks but were more sexually stimulated by the low intensity female-directed displays. Because each pair of high and low intensity playback videos had the exact same audio track, the divergent responses of females must have been based on differences in the visual content of the displays shown in the videos. Preferences female cowbirds show in acoustic CSD studies are correlated with mate choice in field and captivity studies and this is also likely to be true for preferences elucidated by playback of audiovisual displays. Female preferences for low intensity female-directed displays may explain why male cowbirds rarely use high intensity displays when signaling to females. Repetitive high intensity displays may demonstrate a male's current condition and explain why these displays are used in male-male interactions which can escalate into physical fights in which males in poorer condition could be injured or killed. This is the first study in songbirds to use audiovisual playbacks to assess how female sexual behavior varies in response to variation in a male visual display

Wild tree squirrels respond with multisensory enhancement to conspecific robot alarm behaviour.

Natural social communication in animals involves the use of multiple sensory channels but has traditionally been easier to study one channel at a time. As a consequence we know more about the simplified situation of unitary signal channels than we do about the natural situation in which these sources are integrated. Studies of single channels of communication underestimate, and can even misrepresent, the salience and meaning of messages that are normally communicated via multiple channels. However, new mechanical or robotic animal models allow us to test the meaning of multiple components of a signal, via multiple sensory channels. Being three-dimensional, they also allow these questions to be tested in natural field settings where ambient light may constrain other methods such as video playback. Robotic models have been successfully tested with wild amphibians, reptiles and birds. Here we show that a wild mammal, the eastern grey squirrel, Sciurus carolinensis, responds to a robotic model displaying alarm behaviour. Wild squirrels showed enhanced responses to multisensory, audio/visual signals of alarm compared to unisensory (either audio or visual) signals. This is significant for studies of the evolution of communication in that it underscores the importance of taking the complete signal into account, and it provides a method for studying multisensory communication in wild mammals. It is also important for studies of sensory integration, since the squirrels showed an enhanced behavioural response to multisensory signals, providing an overt parallel to brain mechanisms of other mammals that show neural enhancement to multisensory stimuli

Assessing display variability in wild brown anoles \u3cem\u3eAnolis sagrei\u3c/em\u3e using a mechanical lizard model

Signals used for species identity ought to be highly stereotyped so as to facilitate immediate recognition by con-specifics. It is surprising therefore to find variability in putative species signature displays. The brown anole Anolis sagrei has a high degree of variability in its signature bobbing display. In this study we collected descriptive data on variability in the temporal structure of wild brown anole bobbing patterns, finding that no two displays analyzed had the same temporal structure, and we also tested whether wild brown anoles prefer the signature display over an alternate display pattern by using mechanical robot playbacks in the field. As a response metric we assessed whether or not the lizards showed social responses (pushup, dewlap extension, or head-nod) in response to the robotic presentations. We found that the lizards responded slightly more to the signature than to the alternate pattern, providing support for the idea that despite the variability seen in displays, the signature pattern is meaningful to them. We tested two other independent variables: speed of the display and elevation of the robot during its display, neither of which was significant. Dewlap extensions were given predominantly by adult males and were more likely to be given in the breeding season than the nonbreeding season. Pushups and head-nods were given equally by males and a combined class of females and juveniles, and were not seasonal. Head-nods increased after the robot turned off, suggesting that they may be used in a conversational turn-taking style during communication

Assessing display variability in wild brown anoles Anolis sagrei using a mechanical lizard model

Signals used for species identity ought to be highly stereotyped so as to facilitate immediate recognition by conspecifics. It is surprising therefore to find variability in putative species signature displays. The brown anole Anolis sagrei has a high degree of variability in its signature bobbing display. In this study we collected descriptive data on variability in the temporal structure of wild brown anole bobbing patterns, finding that no two displays analyzed had the same temporal structure, and we also tested whether wild brown anoles prefer the signature display over an alternate display pattern by using mechanical robot playbacks in the field. As a response metric we assessed whether or not the lizards showed social responses (pushup, dewlap extension, or head-nod) in response to the robotic presentations. We found that the lizards responded slightly more to the signature than to the alternate pattern, providing support for the idea that despite the variability seen in displays, the signature pattern is meaningful to them. We tested two other independent variables: speed of the display and elevation of the robot during its display, neither of which was significant. Dewlap extensions were given predominantly by adult males and were more likely to be given in the breeding season than the nonbreeding season. Pushups and head-nods were given equally by males and a combined class of females and juveniles, and were not seasonal. Head-nods increased after the robot turned off, suggesting that they may be used in a conversational turn-taking style during communication [Current Zoology 57 (2): 140–152, 2011]

Disruption of the HIF-1 pathway in individuals with Ollier disease and Maffucci syndrome.

Ollier disease (OD) and Maffucci Syndrome (MS) are rare disorders characterized by multiple enchondromas, commonly causing bone deformities, limb length discrepancies, and pathological fractures. MS is distinguished from OD by the development of vascular anomalies. Both disorders are cancer predisposition syndromes with malignancies developing in ~50% of the individuals with OD or MS. Somatic gain-of-function variants in IDH1 and IDH2 have been described in the enchondromas, vascular anomalies and chondrosarcomas of approximately 80% of the individuals with OD and MS. To date, however, no investigation of germline causative variants for these diseases has been comprehensively performed. To search for germline causative variants, we performed whole exome sequencing or whole genome sequencing of blood or saliva DNA in 94 unrelated probands (68 trios). We found that 7 had rare germline missense variants in HIF1A, 6 had rare germline missense variants in VHL, and 3 had IDH1 variants including 2 with mosaic IDH1-p.Arg132His variant. A burden analysis using 94 probands assigned as cases and 2,054 unrelated individuals presenting no OD- or MS-related features as controls, found that variants in HIF1A, VHL, and IDH1 were all significantly enriched in cases compared to controls. To further investigate the role of HIF-1 pathway in the pathogenesis of OD and MS, we performed RNA sequencing of fibroblasts from 4 probands with OD or MS at normoxia and at hypoxia. When cultured in hypoxic conditions, both proband and control cells showed altered expression of a subset of HIF-1 regulated genes. However, the set of differentially expressed genes in proband fibroblasts included a significantly reduced number of HIF-1 regulated genes compared to controls. Our findings suggest that germline or early post-zygotic variants identified in HIF1A, VHL, and IDH1 in probands with OD and MS underlie the development of the phenotypic abnormalities in a subset of individuals with OD and MS, but extensive functional studies are needed to further confirm it

The numbers of differentially expressed genes with a p-value less than 0.05 are shown for each comparison.

See S1–S4 Tables for full lists of significant differentially expressed genes.</p

Burden analysis results showing statistically significant difference when comparing the number of rare functional variants in the proband group to the control group for <i>HIF1A</i>, <i>VHL</i>, and <i>IDH1</i>.

Burden analysis results showing statistically significant difference when comparing the number of rare functional variants in the proband group to the control group for HIF1A, VHL, and IDH1.</p

Top five g:Profiler results for each category from the analysis of 363 genes differentially expressed in three proband fibroblast lines cultured at hypoxia compared to the same three proband fibroblast lines cultured at normoxia.

Analysis was performed using the default settings and selecting the Ensembl ID with the most annotations for each gene name. The p-value cut-off was 0.05 after g:SCS significance adjustment. If number of significant genes in g:Profiler term is greater than 50, n is shown; full lists are available upon request. (PDF)</p