Fat and Body Mass Predict Residency Status in Two Tropical Satyrine Butterflies

Among insect species that compete for ownership of mating sites via aerial interactions, there is little consensus about how morphological and physiological traits functionally translate into costs during a fight. In this study, we evaluated the hypothesis that in territorial disputes without physical contact, traits that maximize endurance will be important determinants of winning. To evaluate the occurrence of physical contact, we used high‐speed video recording (240 frames per second) in two previously unstudied satyrine butterflies: Hermeuptychia fallax and Moneuptychia soter. Additionally, we performed removal experiments to assess whether wing wear, body mass, fat content, and flight muscle ratio are important determinants of male residency status. We filmed a total of 23 fights in H. fallax and 10 in M. soter. Neither species employed physical contact to settle contests. In H. fallax, younger males with greater fat content accumulated in the resident role (n = 26 pairs), indicating that males of this species may compete via ‘endurance contests’. On the other hand, resident males of M. soter were heavier than replacements (n = 11 pairs), but did not differ in any other measured trait. Because disputes occurred without physical contact, it is difficult to imagine how mass or size may functionally affect the chances of victory. Body mass may be related to other unmeasured traits such as condition, parasitic load, or even specific aerodynamic designs related to flight speed or maneuverability.     

Body Size Correlates with Fertilization Success but not Gonad Size in Grass Goby Territorial Males

In fish species with alternative male mating tactics, sperm competition typically occurs when small males that are unsuccessful in direct contests steal fertilization opportunities from large dominant males. In the grass goby Zosterisessor ophiocephalus, large territorial males defend and court females from nest sites, while small sneaker males obtain matings by sneaking into nests. Parentage assignment of 688 eggs from 8 different nests sampled in the 2003–2004 breeding season revealed a high level of sperm competition. Fertilization success of territorial males was very high but in all nests sneakers also contributed to the progeny. In territorial males, fertilization success correlated positively with male body size. Gonadal investment was explored in a sample of 126 grass gobies collected during the period 1995–1996 in the same area (61 territorial males and 65 sneakers). Correlation between body weight and testis weight was positive and significant for sneaker males, while correlation was virtually equal to zero in territorial males. That body size in territorial males is correlated with fertilization success but not gonad size suggests that males allocate much more energy into growth and relatively little into sperm production once the needed size to become territorial is attained. The increased paternity of larger territorial males might be due to a more effective defense of the nest in comparison with smaller territorial males.     

Body Condition Indices Predict Reproductive Success but Not Survival in a Sedentary,Tropical Bird

Body condition may predict individual fitness because those in better condition have more resources to allocate towards improving their fitness. However, the hypothesis that condition indices are meaningful proxies for fitness has been questioned. Here, we ask if intraspecific variation in condition indices predicts annual reproductive success and survival. We monitored a population of Neochmia phaeton (crimson finch), a sedentary, tropical passerine, for reproductive success and survival over four breeding seasons, and sampled them for commonly used condition indices: mass adjusted for body size, muscle and fat scores, packed cell volume, hemoglobin concentration, total plasma protein, and heterophil to lymphocyte ratio. Our study population is well suited for this research because individuals forage in common areas and do not hold territories such that variation in condition between individuals is not confounded by differences in habitat quality. Furthermore, we controlled for factors that are known to impact condition indices in our study population (e.g., breeding stage) such that we assessed individual condition relative to others in the same context. Condition indices that reflect energy reserves predicted both the probability of an individual fledging young and the number of young produced that survived to independence, but only during some years. Those that were relatively heavy for their body size produced about three times more independent young compared to light individuals. That energy reserves are a meaningful predictor of reproductive success in a sedentary passerine supports the idea that energy reserves are at least sometimes predictors of fitness. However, hematological indices failed to predict reproductive success and none of the indices predicted survival. Therefore, some but not all condition indices may be informative, but because we found that most indices did not predict any component of fitness, we question the ubiquitous interpretation of condition indices as surrogates for individual quality and fitness.     

Lean Body Mass Predicts Long-Term Survival in Chinese Patients on Peritoneal Dialysis

Background

Reduced lean body mass (LBM) is one of the main indicators in malnutrition inflammation syndrome among patients on dialysis. However, the influence of LBM on peritoneal dialysis (PD) patients’ outcomes and the factors related to increasing LBM are seldom reported.

Methods

We enrolled 103 incident PD patients between 2002 and 2003, and followed them until December 2011. Clinical characteristics, PD-associated parameters, residual renal function, and serum chemistry profiles of each patient were collected at 1 month and 1 year after initiating PD. LBM was estimated using creatinine index corrected with body weight. Multiple linear regression analysis, Kaplan–Meier survival analysis, and Cox regression proportional hazard analysis were used to define independent variables and compare survival between groups.

Results

Using the median LBM value (70% for men and 64% for women), patients were divided into group 1 (n = 52; low LBM) and group 2 (n = 51; high LBM). Group 1 patients had higher rates of peritonitis (1.6 vs. 1.1/100 patient months; p<0.05) and hospitalization (14.6 vs. 9.7/100 patient months; p<0.05). Group 1 patients also had shorter overall survival and technique survival (p<0.01). Each percentage point increase in LBM reduced the hazard ratio for mortality by 8% after adjustment for diabetes, age, sex, and body mass index (BMI). Changes in residual renal function and protein catabolic rate were independently associated with changes in LBM in the first year of PD.

Conclusions

LBM serves as a good parameter in addition to BMI to predict the survival of patients on PD. Preserving residual renal function and increasing protein intake can increase LBM.     

In-Kennel Behavior Predicts Length of Stay in Shelter Dogs

Previous empirical evaluations of training programs aimed at improving dog adoption rates assume that dogs exhibiting certain behaviors are more adoptable. However, no systematic data are available to indicate that the spontaneous behavior of shelter dogs has an effect on adopter preference. The aim of the present study was to determine whether any behaviors that dogs exhibit spontaneously in the presence of potential adopters were associated with the dogs'' length of stay in the shelter. A sample of 289 dogs was videotaped for 1 min daily throughout their stay at a county shelter. To account for differences in adopter behavior, experimenters varied from solitary passive observers to pairs of interactive observers. Dogs behaved more attentively to active observers. To account for adopter preference for morphology, dogs were divided into “morphologically preferred” and “non-preferred” groups. Morphologically preferred dogs were small, long coated, ratters, herders, and lap dogs. No theoretically significant differences in behavior were observed between the two different dog morphologies. When accounting for morphological preference, three behaviors were found to have a significant effect on length of stay in all dogs: leaning or rubbing on the enclosure wall (increased median length of stay by 30 days), facing away from the front of the enclosure (increased by 15 days), and standing (increased by 7 days). When combinations of behaviors were assessed, back and forth motion was found to predict a longer stay (increased by 24 days). No consistent behavioral changes were observed due to time spent at the shelter. These findings will allow shelters to focus behavioral modification efforts only on behaviors likely to influence adopters'' choices.     

Light Trapping Effect in Wing Scales of Butterfly Papilio peranthus and Its Simulations

Broadband light trapping effect and arrays of sub-wavelength textured structures based on the butterfly wing scales are applicable to solar cells and stealth technologies. In this paper, the fine optical structures in wing scales of butterfly Papilio peranthus, exhibiting efficient light trapping effect, were carefully examined. First, the reflectivity was measured by reflectance spectrum. Field Emission Scanning Electronic Microscope (FESEM) and Transmission Electron Microscope (TEM) were used to observe the coupling morphologies and structures of the scales. Then, the optimized 3D model of the coupling structure was created combining Scanning Electron Microscope (SEM) and TEM data. Afterwards, the mechanism of the light trapping effect of these structures was analyzed by simulation and theoretical calculations. A multilayer nano-structure of chitin and air was found. These structures are effective in increasing optical path, resulting in that most of the incident light can be trapped and adsorbed within the structure at last. Furthermore, the simulated optical results are consistent with the experimental and calculated ones. This result reliably confirms that these structures induce an efficient light trapping effect. This work can be used as a reference for in-depth study on the fabrication of highly efficient bionic optical devices, such as solar cells, photo detectors, high-contrast, antiglare, and so forth.     

Ultraviolet Ornamentation and Male Mating Success in a High-Density Assemblage of the Butterfly Colias eurytheme

Ultraviolet (UV) colour patterns, particularly those deriving from surface structures, serve a role in sexual signalling and mate choice in a range of animal groups. In the butterfly Colias eurytheme (Pieridae), male-limited iridescent UV functions in species recognition, and has potential as an intraspecific sexual signal of mate quality. I compared the dorsal colouration and body size of males discovered ‘in-copula’ (N = 95) with a random sample of free-flying individuals (N = 129), both collected from a high density agricultural population located in Chandler, U.S.A. Despite reasonable variance in each trait, I found no among-group differences in UV characters (brightness, hue and angular visibility) or in the coincident pigmentary yellowish-orange (brightness and saturation). Statistical power was sufficient to detect all but the smallest among-group differences, and there was a marginally significant tendency for in-copula males to be larger. These data do not support the hypothesis for intraspecific female choice upon male dorsal colouration. However, I discuss how the density and apparently very young age of individuals in the sampling population may have pre-disposed this result, and thus, how sexual selection on male colouration may operate in a density dependent manner.     

Early Comers Become Owners: Effect of Residency Experience on Territorial Contest Dynamics in a Lycaenid Butterfly

A positive relationship between ownership and contest success is widespread among territorial butterflies. We tested the hypothesis that owners win simply because they have a longer experience occupying a given territory than do intruders in territorial butterflies. Using the lycaenid butterfly Chrysozephyrus smaragdinus , we staged contests between two males that had experienced different residency periods at the same contested territory, similar to owners and intruders in natural contests. We found that males that had occupied the contested territory for a longer period (a day) always defeated the shorter occupancy males (15 min). Therefore, residency period plays a key role in settling territorial contests. As residency confers advantages in a time-dependent manner, the mechanism of owner dominance could be an increase in motivation to fight as local familiarity increases. Moreover, this result predicts a population-level territorial dynamics. If residency period per se confers advantages in each contest, males arriving at a territory early in their adult season should acquire territorial dominance because they can remain there for a certain period with only a few rivals; late-appearing males do not have this advantage. As predicted, we found that males appearing at territory sites early in the season were more likely to hold their territories. This finding provides new evidence for the evolution of protandry in butterflies.     

Production of [14C]-Labeled 3-Hydroxy-L-Kynurenine in a Butterfly,Heliconius charitonia L. (Heliconidae), and Precursor Studies in Butterfly Wing Ommatins

A method was developed to produce radiolabeled 3-hydroxy-L-kynurenine by injection of [¹⁴C]-L-tryptophan into pupae of the heliconid butterfly, Heliconius charitonia, which was converted into [¹⁴C]-3-hydroxy-L-kynurenine and deposited as a wing pigment. Extractions of 3-hydroxykynurenine (3-OHK) with 60% methanol from wings yielded in 14.4 μg per mg dry weight. In extracts from yellow wing areas, 3-OHK represented 100% of detectable amino acids. Resulting specific radioactivity of [¹⁴C]-3-OHK was between 0.05 and 0.07 mCi/mmol when 0.5 μCi [¹⁴C]-tryptophan was injected into pupae 1 or 2 days before emergence of the butterfly. Incorporation of [¹⁴C]-3-OHK into wing ommochromes was studied in nymphalid butterflies, Araschnia levana and Precis coenia. After injection into pupae [^I4C]-3-OHK as well as [¹⁴C]-tryptophan were specifically incorporated into red and red-brown wing scales as shown by autoradiography. The same incorporation occurred in isolated wings after incubation in Grace's medium containing [¹⁴C]-3-OHK. In Araschnia levana, [¹⁴C]-3-OHK offered to left wing pairs was incorporated into dihydroxanthommatin six times more effectively than [¹⁴C]-tryptophan offered to right wing pairs from the same specimen. Therefore, 3-OHK seems to be the ultimate precursor of wing ommatins.     

Ants as Indicators of Restoration Success at a Uranium Mine in Tropical Australia

The composition and structure of ant communities were used to assess the success of the preliminary restoration program at Ranger uranium mine in the seasonal tropics of northern Australia. Ants were surveyed at eight sites, including two relatively undisturbed control sits, within the Ranger lease. The revegetated sites represented a range of variables likely to influence restoration success: revegetation age (two, four, and eight years), proximity to undisturbed sites (which act as potential sources of recolonization), and burning treatment. Revegetation at most sites was dominated by fast-growing species of Acacia. There was a clear succession of ant species across revegetated sites. Initial colonization was by species of Iridomyrmex, but as plant cover and litter development increased these were replaced by broadly adapted, opportunist species, especially the introduced Paratrechina longicornis. Ant recolonization was very slow at isolated sites, with only 12 species present after eight years (the oldest site available). This compares with 21 species after only four years at a site located close to potential sources of recolonization. The ant community at this site, however, was very similar to that at another site located close to colonization sources, but eight years old. Ant succession therefore appeared to have stalled at this point, with species richness and composition bearing little resemblance to that at control sites. The heavy shade and litter produced by acacias were considered to be the major impediment to further change. Results from a site that had undergone a prescribed burn after two years, thereby breaking dominance by acacias and allowing for the establishment of a wide variety of plant taxa, suggest that such management practices may promote further colonization by ant species.     

Fluctuating Asymmetry and Male Mating Success in a Sphragis-Bearing Butterfly Luehdorfia japonica (Lepidoptera: Papilionidae)

The relationship between fluctuating asymmetry (FA) and mating success was studied within males of the sphragis-baring butterfly Luehdorfia japonica, which were collected at various periods during their mating season. FA was measured on the forewing and hindwing radius lengths of male butterflies. Mating frequency of males was estimated by assessing the degree of scale loss from their claspers. Males consume scales and use them to form sphragis on the female abdomen during copulation, sealing the ostium bursa for life. Age of males was scored as wing age 0 to 4 according to the wearing of the wing. FA was negatively correlated with mating frequency but positively correlated with wing age, and average FA decreased with mating season. As females have little chance to express mate choice, it is likely that FA is an indicator of male viability: symmetrical males live longer and/or fly more actively, resulting in a higher lifetime mating success compared to asymmetrical males.     

Aerodynamic Interactions Between Wing and Body of a Model Insect in Forward Flight and Maneuvers

The aerodynamic interactions between the body and the wings of a model insect in forward flight and maneuvers are studied using the method of numerically solving the Navier-Stokes equations over moving overset grids. Three cases are considered, including a complete insect, wing pair only and body only. By comparing the results of these cases, the interaction effect between the body and the wing pair can be identified. The changes in the force and moment coefficients of the wing pair due to the presence of the body are less than 4.5% of the mean vertical force coefficient of the model insect; the changes in the aerodynamic force coefficients of the body due to the presence of the wings are less than 5.0% of the mean vertical force coefficient of the model insect. The results of this paper indicate that in studying the aerodynamics and flight dynamics of a flapping insect in forward flight or maneuver, separately computing (or measuring) the aerodynamic forces and moments on the wing pair and on the body could be a good approximation.     

Population Densities,Vegetation Green-Up,and Plant Productivity: Impacts on Reproductive Success and Juvenile Body Mass in Reindeer

Global warming is expected to cause earlier springs and increased primary productivity in the Arctic. These changes may improve food availability for Arctic herbivores, but may also have negative effects by generating a mismatch between the surge of high quality food in the spring and the timing of reproduction. We analyzed a 10 year dataset of satellite derived measures of vegetation green-up, population densities, calf body masses and female reproductive success in 19 reindeer (Rangifer tarandus) populations in Northern Norway. An early onset of spring and high peak plant productivity had positive effects on calf autumn body masses and female reproductive success. In addition, body masses and reproductive success were both negatively related to population density. The quantity of food available, as determined by the onset of vegetation green-up and plant productivity over the summer were the main drivers of body mass growth and reproductive success. We found no evidence for an effect of the speed of spring green-up. Nor did we detect a negative mismatch between early springs and subsequent recruitment. Effects of global warming on plant productivity and onset of spring is likely to positively affect sub-Arctic reindeer.     

A Second Dimension to the Leaf Economics Spectrum Predicts Edaphic Habitat Association in a Tropical Forest

Background

Strong patterns of habitat association are frequent among tropical forest trees and contribute to the maintenance of biodiversity. The relation of edaphic differentiation to tradeoffs among leaf functional traits is less clear, but may provide insights into mechanisms of habitat partitioning in these species rich assemblages.

Methodology/Principal Findings

We quantify the leaf economics spectrum (LES) for 16 tree species within a Bornean forest characterized by highly pronounced habitat specialization. Our findings suggest that the primary axis of trait variation in light-limited, lowland tropical forests was identical to the LES and corresponds with the shade tolerance continuum. There was no separation with respect to edaphic variation along this primary axis of trait variation. However, a second orthogonal axis determined largely by foliar P concentrations resulted in a near-perfect separation of species occupying distinct soil types within the forest.

Conclusions/Significance

We suggest that this second axis of leaf trait variation represents a “leaf edaphic habitat spectrum” related to foliar P and potentially other nutrients closely linked to geological substrate, and may generally occur in plant communities characterized by strong edaphic resource gradients.     

Acoustic Monitoring Reveals Congruent Patterns of Territorial Singing Behaviour in Male and Female Tropical Wrens

Many animals defend territories against conspecific individuals using acoustic signals. In birds, male vocalizations are known to play a critical role in territory defence. Territorial acoustic signals in females have been poorly studied, perhaps because female song is uncommon in north‐temperate ecosystems. In this study, we compare male vs. female territorial singing behaviour in Neotropical rufous‐and‐white wrens Thryothorus rufalbus, a species where both sexes produce solo songs and often coordinate their songs in vocal duets. We recorded free‐living birds in Costa Rica using an eight‐microphone Acoustic Location System capable of passively triangulating the position of animals based on their vocalizations. We recorded 17 pairs of birds for 2–4 consecutive mornings and calculated the territory of each individual as a 95% fixed kernel estimate around their song posts. We compared territories calculated around male vs. female song posts, including separate analyses of solo vs. duet song posts. These spatial analyses of singing behaviour reveal that males and females use similarly sized territories with more than 60% overlap between breeding partners. Territories calculated based on solo vs. duet song posts were of similar size and similar degrees of overlap. Solos and duets were performed at similar distances from the nest for both sexes. Overall, male and female rufous‐and‐white wrens exhibit very similar spatial territorial singing behaviour, demonstrating congruent patterns of male and female territoriality.