Allometry and ontogeny in Callibia diana Stål (Mantodea: Acanthopidae)

The life-cycle of Callibia diana St?l is described and linear and geometric morphometrics are used for studying allometrics and shape changes throughout this neotropical mantid species' life-cycle. Significant changes were expected in the allometry and shape of the raptorial leg and abdomen, given the importance of hunting and reproduction. The allometric slopes were obtained by using total length as the independent variable. Geometric morphometrics of landmarks were used for frontal femur and tibia. Hunting and reproduction-related structures had the steepest slopes and positive allometries. Negative growth of both disc width and head width found in the last moulting event may be a consequence of prothoracic muscle growth which is responsible for predatory strike strength. The tibial claw and femur of the raptorial leg become larger, while their spines become more orthogonal to the longitudinal axes which may facilitate prey retention. These changes in mantid shape throughout ontogeny were consistent and suggested the resource allocation and development programming of the body that improved reaching distance and prey retention.     

Allometry of the postnatal cranial ontogeny and sexual dimorphism in Otaria byronia (Otariidae)

We studied the cranial postnatal ontogeny of Otaria byronia in order to detect sexual dimorphism in allometric terms, analyzing the rate of growth of functional variables linked to specific capacities as bite and head movements. We used 20 linear measurements to estimate allometric growth applying bivariate and multivariate analyses in females and males separately. Males were also analyzed in two partitioned subsets considering non-adult and adult stages, when the dimorphism is accentuated in order to reach optimal performance for intra-sexual competition. In the comparison of the employed techniques, we detected an empirical relationship between our multivariate results and the ordinary least square bivariate analysis. The quantitative analyses revealed different ontogenetic trajectories between non-adult and adult males in most variables, suggesting that the adult skull is not a scaled version of subadult skull. For instance, variables related with longitudinal dimensions decreased their allometric coefficients when the adult stage was reached, whereas those related with breadth or vertical dimensions increased their values. In adult males this could indicate that skull breadth and height are more important than longitudinal growth, relative to overall skull size. Conversely, inter-sexual comparisons showed that females and non-adult males shared similar ontogenetic growth trends, including more allometric trends than did males along their own ontogenetic trajectory. In general, adult males exhibited higher allometric coefficients than non-adult males in variables associated with bite and sexual behavior, whereas in comparison to females the latter showed higher coefficients values in these variables. Such patterns indicate a complex mode of growth in males beyond the growth extension, and are in partial agreement with changes previously reported for this and other species in the family Otariidae.     

Head proportion and shape of the head of children between 2 and 7 years--results of a longitudinal study

Based upon a longitudinal anthropometric study with integrated picture documentation, the head proportion and head shape of two to seven years old children will be analysed. The study was initiated in April 2002 in the administrative districts of Potsdam and Potsdam-Mittelmark (Germany). 351 boys and girls have been measured and photographed. The children shall be examined up to four years until September 2006 with a half year investigation distance. Twenty-three anthropometric dimensions have been measured including six dimensions of the head. These dimensions of the head are the head length, head breadth, auricular height, interpupillary distance, facial height and lower face height. Furthermore, digital pictures have been taken of each child. So the head of each child can be examined in a frontal view (Norma frontalis) and in a lateral view (Norma lateralis) and will be analysed relating to changing proportions of the head. The results demonstrated and discussed here are based on a longitudinal succession of photos and point out a method to make individual patterns of the changing head proportions and head shape visual on pictures.     

Allometric growth in the Praying mantis Stagmatoptera biocellata

The growth of ten exoskeletal structures has been studied throughout the post-embryonic development in Stagmatoptera biocellata. The selection of an appropriate statistical procedure to analyse the data was discussed. In spite of theoretical prediction the least-squares regression technique turned out to be as efficient as the Bartlett (1949) procedure for studying growth. Longitudinal treatment of longitudinal data proved to be the best method for this kind of analysis. All the dimensions investigated showed some statistically significant degree of allometric growth and could be ascribed to certain class of allometry. The adaptative value of some allometric growth patterns was discussed in terms of physiological efficiency. A hypothesis put forth by Balderrama & Maldonado (1973) about the anatomic relationships between the parts involved in the mantis strike, received clear support from this analysis. A quantitative assessment of Dyar's (1890) and Przibram's (1912) rules and their modifications led us to conclude that they are untenable at least for the mantid Stagmatoptera biocellata. However, some periods of constant growth ratio could be identified during the post-embryonic development and the concept of maximum growth period was put forward as a complementary element for typifying structures.     

The paradox of a wide nasal aperture in cold-adapted Neandertals: a causal assessment

Neandertals have been characterized as possessing features indicative of cold-climate adaptation largely based on ecogeographical morphological patterning found in recent humans. Interestingly, one character that deviates from this pattern is a relatively wide nasal aperture. The ecogeographical patterning of the nasal aperture in recent humans would predict instead that Neandertals should exhibit reduced nasal breadth dimensions. To explain this apparent anomaly it has been argued that a reduction in Neandertal nasal breadth was not possible due to dentognathic constraints on their midfaces via large anterior palatal breadth dimensions, especially large intercanine distances. A complicating factor in understanding the relationship between anterior palate breadth and nasal breadth is that both measurements are also correlated with facial prognathism. It is, therefore, unknown to what degree the relationship between anterior palate breadth and nasal breadth in Neandertals is a function of the pleisiomorphic retention of a prognathic facial skeleton. We used path analysis to test for a causal relationship between intercanine breadth and nasal breadth taking into account the potential effect of facial projection and facial prognathism (i.e., basion-nasion length and basion-prosthion length) using a large sample of geographically diverse recent and fossil Homo. Additionally, we examined the ontogenetic relationship between nasal breadth and intercanine breadth using a longitudinal human growth series to determine whether these variables exhibit similar growth trajectories. The results of these analyses indicate a weaker association between intercanine breadth and nasal breadth than expected, and that more variation in nasal breadth can be explained through basion-prosthion length rather than anterior palatal breadth dimensions. Moreover, the ontogenetic development of anterior palate breadth does not correspond to the growth trajectory of the breadth of the nose. These results explain the apparent paradox of wide piriform apertures in generally cooler climate-adapted Neandertals without resorting to dentognathic constraints, and provide additional insight into both the adaptive and nonadaptive (i.e., neutral) basis for Neandertal facial evolution.     

Effects of X chromosome on size and shape of body: an anthropometric investigation in 47,XXY males

The effects of an extra X chromosome on size and shape of body and head were studied in 47,XXY males; 25 anthropometric measurements were recorded from 29 adult 47,XXY males and compared with those of male relatives and control males. In stature, arm length, leg length, triceps skinfold, and subscapular skinfold 47,XXY males were larger and in biacromial diameter, bideltoid breadth, wrist breadth, and in most head dimensions smaller than normal males. Arm length was increased less than leg length. Increase in stature seemed to be caused solely by increased leg length, and the somewhat feminine proportions in trunk were caused by decrease in biacromial diameter. Correlations of the body and head dimensions between 47,XXY males and their male relatives were found to be normal. The present findings support the earlier proposals that X chromosome carries genes which influence linear growth. It is suggested that the reduction in biacromial diameter is caused by lowered plasma testosterone level which may also have affected sitting height. The control of body and head dimensions seems to be maintained relatively normal.     

The Visual Orientation Strategies of Mantis religiosa and Empusa fasciata Reflect Differences in the Structure of Their Visual Surroundings

In the present study, peering behaviour, which is used to measure distance by the image motion caused by head movement, is examined in two types of mantid. Mantis religiosa inhabits a region of dense grass consisting of uniform, generally uniformly aligned, and closely spaced elements and executes slow, simple peering movements. In contrast, Empusa fasciata climbs about in open regions of shrubs and bushes which consist of irregular, variably aligned and variably spaced elements and it executes comparatively quick, complex peering movements. Hence, it seems that in these two species of mantid, the same orientation mechanism has been adapted to the unique structures of their visual surroundings. Apparently M. religiosa uses motion parallax and E. fasciata uses a combination of motion parallax and forward and backward movements (image expansion/contraction over time) to detect object distances.     

Family resemblance for cranio-facial measurements in Velanti Brahmins from Andhra Pradesh, India

Maximum likelihood estimates of familial correlations are presented for 12 cranio-facial measurements taken on 399 nuclear families from Southern India. Marital resemblance is significantly different from zero for head circumference, head breadth, minimum frontal breadth, bizygomatic breadth, total facial height, and nasal height, but not for bigonial breadth, nose breadth, nose depth, or ear dimensions. All other familial correlations are significantly greater than zero except for the father-daughter correlation for nasal depth. Path analysis with a TAU transmission model with sex effects reveals that family resemblance for head circumference, head length, bigonial breadth, total facial height, and nasal height, but not for bigonial breadth, nose breadth, nose depth, or ear dimensions. All other familial correlations are significantly greater than zero except for the father-daughter correlation for nasal depth. Path analysis with a TAU transmission model with sex effects breadth, and sex effects in transmission were found for head breadth and nose dimensions. Sex effects in this sample may be due to the fact that different anthropometrists were used for male and female subjects.     

Results of the study of selected head measurements of Jena children]

Secular changes of head measurements (frontal breadth, bizygomatic breadth, bigonial breadth, auricular height, morphological facial height, lower face height) are analysed. The data are based on the Jena anthropological investigations of school children from 1975 and 1985. The inclusion of the data of the Jena longitudinal study carried out since 1985 allows an analysis of the further secular trend. Noticeable changes are proved in most of the analysed traits (frontal breadth, bigonial breadth, auricular height, morphological facial height, lower face height) between 1975 and 1985. The vertical measurements show greater percentage differences than the horizontal measurements, which, among other things, results in a relative narrowing of the face. In some head measurements (frontal breadth, bigonial breadth, auricular height) the trends continue after 1985. The secular trends show no obvious connection with the temporal acceleration of the dentition in the probands of the longitudinal study. However, a connection seems to be possible between the accelerated puberal growth spurt of the body height and the puberal growth spurt in some head dimensions.     

Of niches and distributions: range size increases with niche breadth both globally and regionally but regional estimates poorly relate to global estimates

The relationship between species’ niche breadth (i.e. the range of environmental conditions under which a species can persist) and range size (i.e. the extent of its spatial distribution) has mostly been tested within geographically restricted areas but rarely at the global extent. Here, we not only tested the relationship between range size (derived from species’ distribution data) and niche breadth (derived from species’ distribution and co‐occurrence data) of 1255 plant species at the regional extent of the European Alps, but also at the global extent and across both spatial scales for a subset of 180 species. Using correlation analyses, linear models and variation partitioning, we found that species’ realized niche breadth estimated at the regional level is a weak predictor of species’ global niche breadth and range size. Against our expectations, distribution‐derived niche breadth was a better predictor for species’ range size than the co‐occurrence‐based estimate, which should, theoretically, account for more than the climatically determined niche dimensions. Our findings highlight that studies focusing on the niche breadth vs range size relationship must explicitly consider spatial mismatches that might have confounded and diminished previously reported relationships.     

Mechanosensory‐based orientation to elevated prey by a benthic fish

Lake Michigan mottled sculpin, Cottus bairdi, respond to both live and artificial (e.g., vibrating sphere) prey with an unconditioned movement towards the source of vibration, followed by a step‐by‐step approach and final strike at the source. In addition to these well‐studied, whole‐body movements along the horizontal plane of the substrate, sculpin exhibit a little‐studied behavior in which the vertical position of the fish's head can vary from being flush with the substrate to several cm's above the substrate. To test the hypothesis that sculpin can determine source elevation via mechanosensory cues, we measured head elevation of blinded fish as a function of source elevation and distance as fish approached a small (3 mm radius), 50 Hz vibrating sphere. At distances associated with pre‐strike positions (< 2 cm), head elevations were positively correlated with source elevation before but not after pharmacological blocking of the lateral line with CoCl₂. These results demonstrate that sculpin are able to determine source elevation using mechanosensory cues alone and that in the absence of visual and olfactory cues, vertical orientation of the head towards the source requires the lateral line system.     

Morphological adaptations to an unusual defensive strategy in the mantid Orthoderella ornata (Insecta: Mantidae)

The behaviour of Orthoderella ornata Giglio Tos, 1897, a cryptically coloured mantid, is described with reference to some morphological adaptations that conceal the typical insect outline.
The modification of the typical morphology of the head in mantids is analysed with special mention of the internal structure, the tentorium, and by comparison with the disposition of two other species with a different defensive strategy.
The hypothesis that O. ornata has short legs in correlation with its resting position is supported by a morphometric comparison with five other species of mantids which show different behaviour and positions in their cryptic strategy.     

Sexual deception in a cannibalistic mating system? Testing the Femme Fatale hypothesis

Animal communication theory holds that in order to be evolutionarily stable, signals must be honest on average, but significant dishonesty (i.e. deception) by a subset of the population may also evolve. A typical praying mantid mating system involves active mate searching by males, which is guided by airborne sex pheromones in most species for which mate-searching cues have been studied. The Femme Fatale hypothesis suggests that female mantids may be selected to exploit conspecific males as prey if they benefit nutritionally from cannibalism. Such a benefit exists in the false garden mantid Pseudomantis albofimbriata—females use the resources gained from male consumption to significantly increase their body condition and reproductive output. This study aimed to examine the potential for chemical deception among the subset of females most likely to benefit from cannibalism (poorly fed females). Females were placed into one of four feeding treatments (‘Very Poor’, ‘Poor’, ‘Medium’ and ‘Good’), and males were given the opportunity to choose between visually obscured females in each of the treatments. Female body condition and fecundity varied linearly with food quantity; however, female attractiveness did not. That is, Very Poor females attracted significantly more males than any of the other female treatments, even though these females were in significantly poorer condition, less fecund (in this study) and more likely to cannibalise (in a previous study). In addition, there was a positive correlation between fecundity and attractiveness if Very Poor females were removed from the analysis, suggesting an inherently honest signalling system with a subset of dishonest individuals. This is the first empirical study to provide evidence of sexual deception via chemical cues, and the first to provide support for the Femme Fatale hypothesis.     

Craniofacial variation and growth in the Prader-Labhart-Willi syndrome

A study of anthropometric variation and craniofacial growth in individuals with the Prader-Labhart-Willi syndrome (PLWS) illustrates the utility of anthropometry in clinical evaluation and research. Anthropometric measurements, including head length and breadth, minimum frontal diameter, and head circumference, were obtained on 38 PLWS individuals (21 with chromosome 15 deletions) with an age range from 2 weeks to 39 years. No anthropometric differences were found between the two chromosome subgroups. A relative deceleration in the growth of certain craniofacial dimensions (head circumference and length) is suggested by the negative correlations between age and Z-scores for the measurements. Raw values for minimum frontal diameter and head breadth were near or below the 5th percentile curve, while almost all values for head length and circumference fell within normal limits. The data support suggestions that dolichocephaly be considered an early diagnostic feature of PLWS. Furthermore, the status of narrow bifrontal diameter as a major feature of PLWS is confirmed.     

Male mate choice in a sexually cannibalistic species: male escapes from hungry females in the praying mantid <Emphasis Type="Italic">Tenodera angustipennis</Emphasis>

While competing males and choosy females may be common in animal mating systems, male choice can evolve under certain conditions. Sexual cannibalism is such a condition because of the high mortality risk for males. In mantids, female body condition is associated with male mate preference, with fat females preferred, due to at least two reasons: females in poor nutritional condition are likely to attack and predate males, and fat females can potentially increase the number of offspring. Thus, the risk of cannibalism and female fecundity can influence male mating behavior. In this study, we attempted to separate these factors by using the praying mantid Tenodera angustipennis to examine whether male preference for fat female mantids was based on avoiding sexual cannibalism (cannibalism avoidance hypothesis) or preference for female fecundity (fecundity preference hypothesis). The feeding regimes were experimentally manipulated to discriminate between the effects of female fecundity and female hunger status on male and female mating behaviors. We found that recently starved females more frequently locomoted toward the male, and that male abdominal bending was less intensive and escape was sooner from recently starved females. These female and male behavioral responses to female hunger condition may reveal male avoidance of dangerous females in this mantid.     

As to the influence of climate on head form.

In two quite different geographical regions--Mo?ambique and Hierro (an island of the Canaries)--observations have been made which point to an influence of climatic conditions on head dimensions: In localities of higher altitude or/and with colder climate maximum head breadth, minimum frontal breadth and auricular height proved to show higher dimensions compared with localities of milder (more hot) climate.     

Variable effects of wolves on niche breadth and density of intraguild competitors

1. The parallel niche release hypothesis (PNR) indicates that reduced competition with dominant competitors results in greater density and niche breadth of subordinate competitors and which may support an adaptive advantage.
2. We assessed support for the PNR by evaluating relationships between variation in niche breadth and intra‐ and interspecific density (an index of competition) of wolves (Canis lupus) coyotes (C. latrans), and bobcats (Lynx rufus).
3. We estimated population density (wolf track surveys, coyote howl surveys, and bobcat hair snare surveys) and variability in space use (50% core autocorrelated kernel density home range estimators), temporal activity (hourly and overnight speed), and dietary (isotopic δ¹³C and δ¹⁵N) niche breadth of each species across three areas of varying wolf density in the Upper Peninsula of Michigan, USA, 2010–2019.
4. Densities of wolves and coyotes were inversely related, and increased variability in space use, temporal activity, and dietary niche breadth of coyotes was associated with increased coyote density and decreased wolf density supporting the PNR. Variability in space use and temporal activity of wolves and dietary niche breadth of bobcats also increased with increased intraspecific density supporting the PNR.
5. Through demonstrating decreased competition between wolves and coyotes and increased coyote niche breadth and density, our study provides multidimensional support for the PNR. Knowledge of the relationship between niche breadth and population density can inform our understanding of the role of competition in shaping the realized niche of species.

     

Bi-sensory, striped representations: comparative insights from owl and platypus.

Bi-sensory striped arrays are described in owl and platypus that share some similarities with the other variant of bi-sensory striped array found in primate and carnivore striate cortex: ocular dominance columns. Like ocular dominance columns, the owl and platypus striped systems each involve two different topographic arrays that are cut into parallel stripes, and interdigitated, so that higher-order neurons can integrate across both arrays. Unlike ocular dominance stripes, which have a separate array for each eye, the striped array in the middle third of the owl tectum has a separate array for each cerebral hemisphere. Binocular neurons send outputs from both hemispheres to the striped array where they are segregated into parallel stripes according to hemisphere of origin. In platypus primary somatosensory cortex (S1), the two arrays of interdigitated stripes are derived from separate sensory systems in the bill, 40,000 electroreceptors and 60,000 mechanoreceptors. The stripes in platypus S1 cortex produce bimodal electrosensory-mechanosensory neurons with specificity for the time-of-arrival difference between the two systems. This "thunder-and-lightning" system would allow the platypus to estimate the distance of the prey using time disparities generated at the bill between the earlier electrical wave and the later mechanical wave caused by the motion of benthic prey. The functional significance of parallel, striped arrays is not clear, even for the highly-studied ocular dominance system, but a general strategy is proposed here that is based on the detection of temporal disparities between the two arrays that can be used to estimate distance.