Thermal characterization of butterfly wings—1. Absorption in relation to different color, surface structure and basking type

1. 1. Spectral integral reflectance, transmittance and the resulting absorption of intact and descaled butterfly wings of the black-winged Pachliopta aristolochiae (Papilionidae), the white-winged Pieris brassicae (Pieridae), and the yellow-winged Gonepteryx rhamni (Pieridae) were determined between 350 and 800 nm.

2. 2. Whereas in the black forewing of the dorsal basking Pachliopta almost all incident light is absorbed nearly independent of the wavelength and thus converted into heat, the white forewing of the body basking Pieris absorbs less than 20% in the visible range of the spectrum.

3. 3. The yellow hindwing of the lateral basking Gonepteryx absorbs to a higher degree than the Pierid wing, but—due to the sparsely arranged scales—transmittance is clearly increased (40–50% between 525 and 800 nm).

4. 4. The varying thermal characteristics of the different wings with reference to the color and arrangement of the scales and the different basking strategies of the butterflies are discussed.

Fairy wrasses perceive and respond to their deep red fluorescent coloration

Fluorescence enables the display of wavelengths that are absent in the natural environment, offering the potential to generate conspicuous colour contrasts. The marine fairy wrasse Cirrhilabrus solorensis displays prominent fluorescence in the deep red range (650–700 nm). This is remarkable because marine fishes are generally assumed to have poor sensitivity in this part of the visual spectrum. Here, we investigated whether C. solorensis males can perceive the fluorescence featured in this species by testing whether the presence or absence of red fluorescence affects male–male interactions under exclusive blue illumination. Given that males respond aggressively towards mirror-image stimuli, we quantified agonistic behaviour against mirrors covered with filters that did or did not absorb long (i.e. red) wavelengths. Males showed significantly fewer agonistic responses when their fluorescent signal was masked, independent of brightness differences. Our results unequivocally show that C. solorensis can see its deep red fluorescent coloration and that this pattern affects male–male interactions. This is the first study to demonstrate that deep red fluorescent body coloration can be perceived and has behavioural significance in a reef fish.     

The Amino Acid Content in Gamma-irradiated Rice†

High phosphate accumulating bacteria were isolated by autoradiography. One isoate, Arthrobacter globiformis PAB-6 accumulated phosphate intracellularly at 20% of dry cell mass in a simple synthetic medium. This amount was 3~7 times higher than type cultures examined. Almost no phosphate was released into the medium after cessation of growth. Fifty percent of total intracellular phosphate was fractionated as nucleic acids, while 20% each was recovered from cold PCA soluble fractions and polyphosphate fractions. The large content of nucleic acids in this bacterium appeared due to increased RNA content, specifically 4 S RNA fraction.     

Coevolution of visual signals and eye morphology in Polistes paper wasps

To be effective, signals must propagate through the environment and be detected by receivers. As a result, signal form evolves in response to both the constraints imposed by the transmission environment and receiver perceptual abilities. Little work has examined the extent to which signals may act as selective forces on receiver sensory systems to improve the efficacy of communication. If receivers benefit from accurate signal assessment, selection could favour sensory organs that improve discrimination of established signals. Here, we provide evidence that visual resolution coevolves with visual signals in Polistes wasps. Multiple Polistes species have variable facial patterns that function as social signals, whereas other species lack visual signals. Analysis of 19 Polistes species shows that maximum eye facet size is positively associated with both eye size and presence of visual signals. Relatively larger facets within the eye''s acute zone improve resolution of small images, such as wasp facial signals. Therefore, sensory systems may evolve to optimize signal assessment. Sensory adaptations to facilitate signal detection may represent an overlooked area of the evolution of animal communication.     

FITNESS CONSEQUENCES OF SEASONAL POLYPHENISM IN WESTERN WHITE BUTTERFLIES

The western white butterfly, Pontia occidentalis, has distinctly different wing phenotypes during spring and summer generations as a result of phenotypic plasticity (seasonal polyphenism). We experimentally generated different seasonal phenotypes in the lab by altering photoperiodic conditions during rearing, and released the resulting butterflies in the field. Mark-recapture studies were then used to estimate the effects of the polyphenism on activity patterns and adult survival in both late-spring (one study) and summer (two studies) conditions. There were no significant effects of rearing treatment on temporal patterns of behavioral activity during either the late-spring or the summer field studies. Recapture probabilities were consistently higher for males than females in all three field studies; in the summer 1992 study, recapture probabilities were higher for long-day (LD) than for short-day (SD) treatment groups. During the late-spring 1992 study, there were no significant differences between LD and SD treatment groups for survival probabilities. In the two summer studies, there were significant effects of photoperiodic treatment on survival probabilities; in the summer 1992 study, LD individuals consistently had higher survival probabilities than SD individuals; in the summer 1991 study, there was a significant interaction between treatment and time period on survival probabilities, such that survival probabilities were higher for LD than for SD individuals in two of four time periods. The consistent differences in survival probabilities between treatment groups in the summer 1992 study can be accounted for by the differences in wing traits between the treatment groups. Micrometeorological data from the study site showed that midday ambient temperatures averaged ~3°C hotter during the 1992 than the 1991 summer study and that ambient conditions during the late-spring 1992 study were relatively warm and sunny for the season. These results document the varying relationships between phenotype and fitness in the temporally fluctuating environments experienced by this population.     

Experimental evidence that egg color indicates female condition at laying in a songbird

The signaling hypothesis of eggshell coloration in birds isbased on the assumption that females of species with blue-greeneggs signal their phenotypic quality to their mates throughdeposition of the antioxidant biliverdin as pigment. Egg pigmentationmay be an expression of the condition of females at laying orof genetic linkages between egg color and female performancevariables. We have supplemented 16 pied flycatcher, Ficedulahypoleuca, females with mealworms before and during laying andcompared the mass and color of their eggs as measured on theday of laying to those of 16 control females with the same nestconstruction and laying dates and clutch sizes. Supplementedfemales laid significantly heavier and more intensely blue-greeneggs than control females. Egg blue-green chroma was significantlyassociated with the amount of biliverdin in eggshells. Egg color,and thus biliverdin content, is an expression of female conditionat laying.     

Darker female pigeons transmit more specific antibodies to their eggs than do paler ones

Melanin‐based coloration is widespread among vertebrates, yet the adaptive significance of such pigments remains elusive, particularly with regard to the link between melanin and immune‐mediated maternal effects. The aim of this study was to investigate whether melanin‐based coloration could signal the ability of mothers to mount a humoral response and to transfer maternal antibodies (Ab) to their young. We injected differently coloured (pale and dark) female feral pigeons (Columba livia) with Chlamydiae (a natural antigen) and Keyhole Limpet Haemocyanin (KLH, an artificial antigen), and found no significant difference in humoral response between differently coloured females. However, darker females transferred more Ab against Chlamydiae into their eggs than paler ones, despite similar circulating levels of Ab. In addition to this, melanin‐based coloration showed a high heritability value. This suggests that a genetically based coloured trait might be linked to the ability of females to transfer specific Ab against Chlamydiae (but not against KLH) to their offspring, independent of their ability to produce Ab. This suggests that transmission of maternal Ab is antigen dependent, and that melanin‐based coloration might signal female ability to transmit specific Ab against natural pathogens. © 2013 The Linnean Society of London     

Predation on snakes of Argentina: Effects of coloration and ring pattern on coral and false coral snakes

The occurrence of coral snake coloration among unrelated venomous and non‐venomous snake species has often been explained in terms of warning coloration and mimicry. In Argentina, no field tests have been conducted to confirm this mimetic association between one venomous coral species (Micrurus phyrrocryptus, Elapidae) and two non‐venomous snake species with a similar color pattern (Lystrophis pulcher and Oxyrhopus rhombifer, Colubridae). The aims of this work were to test for the possible aposematic or cryptic function of the ring pattern and coloration of coral snakes and false coral snakes from central Argentina, and to analyse whether the pattern is effective throughout the year. Predation on snakes was estimated by using non‐toxic plasticine replicas of ringed venomous and non‐venomous snakes and unbanded green snakes placed along transects in their natural habitat during the dry and rainy season. Ringed color pattern was attacked by predators despite the background color. One of the replica types was attacked more than expected during the dry season, suggesting that both shape and width of rings may influence the choice by predators. The reaction of predators towards replicas that mimic snake species with ringed patterns is independent of the geographical region, and we can conclude that mimicry characteristics are quite general when the true models are present in the area.