Temperate-zone Species Research Articles

Diet and Feeding Ecology of Crotalus tzabcan (Serpentes: Viperidae)

The Tzabcan rattlesnake (Crotalus tzabcan) is endemic to the Yucatan Peninsula and is part of the C. durissus complex. Although relatively widespread, it is rather an uncommon species; therefore, little is known about its natural history. Herein, we describe the diet of C. tzabcan on the basis of data from field encounters, museum specimens, and published data. Dietary samples were collected from Campeche, Quintana Roo, and Yucatan, Mexico, and literature records from Belize, representing most of the species' distribution range. Examination of 50 individuals resulted in 28 prey items obtained from 27 snakes. The diet of C. tzabcan consisted exclusively of mammals, including the orders Rodentia (86% of the prey items) and Soricomorpha (7%), and no ontogenetic shift in prey type was detected. However, an ontogenetic telescope is evident, where adults consume larger prey than juveniles but continue feeding on small prey. No sexual dimorphism in snout–vent length and total length was detected in C. tzabcan. No sexual differences in prey mass were found when controlling for snake body length, nor when comparing between sexes in adults and juveniles. The presence of prey was not related to snake collection date, suggesting year-round feeding. There was no difference in prey class and size among snakes from Yucatan dry forest and moist forest. These results suggest a homogenous diet among sexes, seasons, and populations. This is the first detailed study on the diet and feeding ecology of C. tzabcan, and it adds five new prey species: Cryptotys mayensis, Heteromys desmarestianus, H. gaumeri, Oryzomys couesi, and Rattus rattus, as well as two previously reported ones: Mus musculus and Sigmodon toltecus. These findings contrast with anecdotal reports of C. tzabcan consuming reptiles and birds and show many similarities with the related species C. durissus. Additional studies on the natural history of C. tzabcan and related species would help to better understand how the feeding ecology of Neotropical rattlesnakes differs from those species of temperate zones.

Can mixed pine forests conserve understory richness by improving the establishment of understory species typical of native oak forests?

A positive effect of mixed pine forests ( Pinus sylvestris L. and Pinus pinaster Ait.) on the understory richness and tree regeneration was observed with respect to monospecific stands. Understory species typical of the native Pyrenean oak forests in the Iberian Peninsula contribute to maintaining high understory richness in such mixed pine forests. The influence of stands characteristics on the understory in mixtures that combine coniferous tree species of the same genus deserves more study since they are frequent in Spain. To assess the effect of mixed versus monospecific stands of Pinus sylvestris L. and Pinus pinaster Ait. on the main tree species regeneration and understory species composition. Tree regeneration and understory species composition were inventoried in eighteen forest plots (6 triplets) in North-Central Spain. Each triplet consisted of two plots dominated either by Scots pine or Maritime pine and one mixed plot that contained both species. The basal area (%) of both Pinus species was the only characteristic of the stands that significantly influenced the understory composition and tree regeneration. Characteristic species of humid and temperate zones, including P. sylvestris regeneration, dominated in Scots pine stands, and typical species of well-drained Mediterranean areas, including P. pinaster regeneration, dominated in Maritime pine stands. In mixed stands, the highest regeneration of the native Pyrenean oak with respect to monospecific stands was accompanied by understory species typical of native oak forests that share the same regeneration niche. Mixed pine forests allow the development of understory species better than monospecific forests.

Nut crops collection of "Ustymivskyi" dentrological park

Aim. The aim of the work is to characterize the diversity of nut crops in terms of the efficiency of introduction in the conditions of the southern forest-steppe of Ukraine. Results and Discussion. In the collection of tree and shrub species of the State Dendrological Park "Ustymivskyi" numbering 472 species, nut crops are represented by more than 120 species. These include fruit species of temperate and subtropical zones from different botanical families. The climate in the area of the park is moderately continental with unstable humidity, frequent snowless winters with sharp fluctuations in air temperature. Dry winds are 2-3 times a year. The amount of precipitation is 254-777 mm per year. In the spring-summer period, there are periods without rain (up to two to three months). As a result of the study, the species and forms promising for introduction in such conditions have been identified. These are representatives of the genus Juglans: J. mandshurica Maxim. (Manchurian walnut), J. cinerea L. (gray walnut), J. nigra L. (black walnut) and J. regia L. (walnut). Corylus colurna (bear hazelnut) showed exceptionally good growth and abundant fruiting. However, in the last 10 years, the trees have become dry top and dry. Shrub species C. avellana (its forms 'Purpurea', 'Laciniata') and C. pontica C. Koch. turned out to be more adapted to climate change. The endemic steppe species Amygdalus nana L. (steppe almond) can be recommended in crosses when breeding for winter hardiness and an increased content of the alkaloid amygdalin (up to 4.5%). A. triloba Ricker. (almond three-bladed, regular and terry forms) is used as a decorative type. However, due to excessive disease damage (cercosporosis, orange spot, curly leaves, burns), plants lose their decorative effect. Repeated attempts to introduce into the collection such species as Carya alba (L.) C. Koch. (pignut hickory), Pterocarya pterocarpa (Michx.) Kunth ex Iljinsk. (caucasian wingnut), Fagus sylvatica L. (common beech) and Castanea sativa Mill. (sowing chestnut) were unsuccessful: the plants quickly died. Success has been achieved in the introduction and distribution of Xanthoceras sorbifolium and Ginkgo biloba in the forest-steppe and steppe zones. Conclusions. It is recommended to introduce walnut crops isolated as a result of the study into the range of plants used in landscaping, to create perennial plantations on lands unsuitable for agricultural production.

Australian songbird body size tracks climate variation: 82 species over 50 years.

The observed variation in the body size responses of endotherms to climate change may be explained by two hypotheses: the size increases with climate variability (the starvation resistance hypothesis) and the size shrinks as mean temperatures rise (the heat exchange hypothesis). Across 82 Australian passerine species over 50 years, shrinking was associated with annual mean temperature rise exceeding 0.012°C driven by rising winter temperatures for arid and temperate zone species. We propose the warming winters hypothesis to explain this response. However, where average summer temperatures exceeded 34°C, species experiencing annual rise over 0.0116°C tended towards increasing size. Results suggest a broad-scale physiological response to changing climate, with size trends probably reflecting the relative strength of selection pressures across a climatic regime. Critically, a given amount of temperature change will have varying effects on phenotype depending on the season in which it occurs, masking the generality of size patterns associated with temperature change. Rather than phenotypic plasticity, and assuming body size is heritable, results suggest selective loss or gain of particular phenotypes could generate evolutionary change but may be difficult to detect with current warming rates.

Behavioral evidence for sex steroids hypersensitivity in castrated male canaries

In seasonally breeding songbirds such as canaries, singing behavior is predominantly under the control of testosterone and its metabolites. Short daylengths in the fall that break photorefractoriness are followed by increasing daylengths in spring that activate singing via both photoperiodic and hormonal mechanisms. However, we observed in a group of castrated male Fife fancy canaries maintained for a long duration under a short day photoperiod a large proportion of subjects that sang at high rates. This singing rate was not correlated with variation in the low circulating concentrations of testosterone. Treatment of these actively singing castrated male canaries with a combination of an aromatase inhibitor (ATD) and an androgen receptor blocker (flutamide) only marginally decreased this singing activity as compared to control untreated birds and did not affect various measures of song quality. The volumes of HVC and of the medial preoptic nucleus (POM) were also unaffected by these treatments but were relatively large and similar to volumes in testosterone-treated males. In contrast, peripheral androgen-sensitive structures such as the cloacal protuberance and syrinx mass were small, similar to what is observed in castrates. Together these data suggest that after a long-term steroid deprivation singing behavior can be activated by very low concentrations of testosterone. Singing normally depends on the activation by testosterone and its metabolites of multiple downstream neurochemical systems such as catecholamines, nonapeptides or opioids. These transmitter systems might become hypersensitive to steroid action after long term castration as they probably are at the end of winter during the annual cycle in seasonally breeding temperate zone species.

Wild zebra finches do not use social information from conspecific reproductive success for nest site choice and clutch size decisions

Information about the quality of local habitat can greatly help to improve an individual’s decision-making and, ultimately, its fitness. Nevertheless, little is known about the mechanisms and significance of information use in reproductive decisions, especially in unpredictable environments. We tested the hypothesis that perceived breeding success of conspecifics serves as a cue for habitat quality and hence influences breeding decisions (nest site choice and clutch size), using the zebra finch (Taeniopygia guttata) as a model species. Zebra finches breed opportunistically in the unpredictable, arid zone of Australia. They often inspect the nests of conspecifics, potentially to prospect on conspecific reproductive success, i.e., to collect social information. We conducted a clutch and brood size manipulation to experimentally create the perception of high and low quality areas. In six areas, clutch sizes of almost 300 zebra finch nests were either all increased (N = 3 areas) or reduced (N = 3 areas) throughout one breeding season. The number of breeding pairs and sizes of newly laid clutches were not significantly affected by the manipulated reproductive success of the areas. Thus, zebra finches did not use social cues for their reproductive decisions, which contrasts with findings of species in temperate zones, and could be an adaptation to the high unpredictability of their habitat. Even the personal experience of rebreeding birds did not directly affect their clutch size. Our study suggests that zebra finches employ a high level of opportunism as a key strategy for reproduction. Further, this is the first study to our knowledge using an experimental approach in the wild to demonstrate that decision-making in unpredictable natural environments might differ from decision-making in temperate environments with seasonal breeding. Social information can help to optimize the behavior of animals. Birds in temperate climates with seasonality use breeding success of others to predict where they should breed. However, very little is known about information use in less predictable environments. In a field experiment, we created a patchy environment by increasing and decreasing brood sizes of wild zebra finches to test if social information is also used in unpredictable conditions. We found no evidence that zebra finches in the Australian outback use social information from their conspecifics when deciding on nest site and clutch size. They probably gather personal information on environmental parameters and the current availability of resources, which might be more reliable than social information.

DIACYLGLYCEROL ACYLTRANSFERASE1 Contributes to Freezing Tolerance.

Freezing limits plant growth and crop productivity, and plant species in temperate zones have the capacity to develop freezing tolerance through complex modulation of gene expression affecting various aspects of metabolism and physiology. While many components of freezing tolerance have been identified in model species under controlled laboratory conditions, little is known about the mechanisms that impart freezing tolerance in natural populations of wild species. Here, we performed a quantitative trait locus (QTL) study of acclimated freezing tolerance in seedlings of Boechera stricta, a highly adapted relative of Arabidopsis (Arabidopsis thaliana) native to the Rocky Mountains. A single QTL was identified that contained the gene encoding ACYL-COENZYME A:DIACYLGLYCEROL ACYLTRANSFERASE1 (BstDGAT1), whose expression is highly cold responsive. The primary metabolic enzyme DGAT1 catalyzes the final step in assembly of triacylglycerol (TAG) by acyl transfer from acyl-CoA to diacylglycerol. Freezing tolerant plants showed higher DGAT1 expression during cold acclimation than more sensitive plants, and this resulted in increased accumulation of TAG in response to subsequent freezing. Levels of oligogalactolipids that are produced by SFR2 (SENSITIVE TO FREEZING2), an indispensable element of freezing tolerance in Arabidopsis, were also higher in freezing-tolerant plants. Furthermore, overexpression of AtDGAT1 led to increased freezing tolerance. We propose that DGAT1 confers freezing tolerance in plants by supporting SFR2-mediated remodeling of chloroplast membranes.

Seasonal variation in energy expenditure in a rodent inhabiting a winter-rainfall desert.

Animals that spend more energy than they obtain risk entering allostatic overload, reducing survival and fitness. They are predicted to adjust their daily energy expenditure (DEE) during periods of food scarcity. Adjustments of DEE to changes in food availability have been well-studied in species in temperate zones during winter, but less so in species enduring seasonal droughts. Likely mechanisms regulating DEE involve adjustments of activity and maintenance metabolism. Species that experience seasonal droughts and changes in food availability, like the African striped mouse (Rhabdomys pumilio), are appropriate model organisms to study the regulation of seasonal changes of DEE. We quantified DEE using the 'doubly labelled water' method, measured resting metabolic rate (RMR), and concomitantly determined activity levels using all-day focal observations of 69 free-living striped mice in the cold moist season with high food availability and the hot dry season with low food availability. Striped mice decreased their DEE in the food scarce dry season using multiple mechanisms, especially reductions in RMR, and reduced overall physical activity. This was further facilitated passively by reduced thermoregulatory costs. Our study demonstrates that animals reduce DEE via active and passive mechanisms in food-restricted environments, and highlights that several environmental factors should be considered simultaneously when aiming to understand how animals cope with harsh environments.

Food Availability Is the Main Driver of Seasonal Changes in Resting Metabolic Rate in African Striped Mice (Rhabdomys pumilio).

Resting metabolic rate (RMR) influences energy allocation to survival, growth, and reproduction, and significant seasonal changes in RMR have been reported. According to one hypothesis, seasonal changes in RMR are mainly attributable to seasonal changes in ambient temperature (Ta) and food availability. Studies on species from the temperate zone indicated that food availability is the main driver. However, whether this is generally true is unknown, because studies from the tropics and subtropics, where most species live, are rare. We studied the African striped mouse (Rhabdomys pumilio) inhabiting a seasonal environment with hot dry seasons with low food availability and cold moist seasons with high food availability. Using 603 RMR measurements of 277 individuals, we investigated the relative importance of food availability and Ta on RMR during selected periods, in which one extrinsic factor varied while the other factor was relatively constant. At similar Ta, residual RMR increased with increasing levels of food availability. In contrast, different Ta did not influence residual RMR at similar levels of food availability. Thus, our study on a subtropical species gives support to the hypothesis, derived from temperate zone species, that food availability mainly drives seasonal changes in RMR.

Apparent annual survival estimates of tropical songbirds better reflect life history variation when based on intensive field methods

AbstractAimAdult survival is central to theories explaining latitudinal gradients in life history strategies. Life history theory predicts higher adult survival in tropical than north temperate regions given lower fecundity and parental effort. Early studies were consistent with this prediction, but standard‐effort netting studies in recent decades suggested that apparent survival rates in temperate and tropical regions strongly overlap. Such results do not fit with life history theory. Targeted marking and resighting of breeding adults yielded higher survival estimates in the tropics, but this approach is thought to overestimate survival because it does not sample social and age classes with lower survival. We compared the effect of field methods on tropical survival estimates and their relationships with life history traits.LocationSabah, Malaysian Borneo.Time period2008–2016.Major taxonPasseriformes.MethodsWe used standard‐effort netting and resighted individuals of all social and age classes of 18 tropical songbird species over 8 years. We compared apparent survival estimates between these two field methods with differing analytical approaches.ResultsEstimated detection and apparent survival probabilities from standard‐effort netting were similar to those from other tropical studies that used standard‐effort netting. Resighting data verified that a high proportion of individuals that were never recaptured in standard‐effort netting remained in the study area, and many were observed breeding. Across all analytical approaches, addition of resighting yielded substantially higher survival estimates than did standard‐effort netting alone. These apparent survival estimates were higher than for temperate zone species, consistent with latitudinal differences in life histories. Moreover, apparent survival estimates from addition of resighting, but not from standard‐effort netting alone, were correlated with parental effort as measured by egg temperature across species.Main conclusionsInclusion of resighting showed that standard‐effort netting alone can negatively bias apparent survival estimates and obscure life history relationships across latitudes and among tropical species.

Demographic history of Heermann's Gull (Larus heermanni) from late Quaternary to present: Effects of past climate change in the Gulf of California

ABSTRACT Climate change during the late Quaternary period (LQP), in both temperate and tropical zones, has been a major driver in the shaping of species distributions and abundances. Our understanding of the various effects of climate change on population dynamics of marine species in temperate zones (such as the Gulf of California) is growing. However, studies on the demographic history of seabirds are rare and there is no description of how regional climate change has affected high-trophic-level marine species such as Heermann's Gull (Larus heermanni; Charadriiformes: Laridae). We investigated whether the demographic history of Heermann's Gull reflects population change consistent with past changes in climate in the Gulf of California during the LQP. We also explored whether those past changes affected the demographic history of codistributed marine organisms in a similar way as found for Heermann's Gulls. To test our hypotheses, we sequenced a fragment of the mitochondrial DNA cytochrome b gene (1,033 ...

Low temperature tolerance, cold hardening and acclimation in tadpoles of the neotropical túngara frog (Engystomops pustulosus)

Many frogs from temperate climates can tolerate low temperatures and increase their thermal tolerance through hardening and acclimation. Most tropical frogs, on the other hand, fail to acclimate to low temperatures. This lack of acclimation ability is potentially due to lack of selection pressure for acclimation because cold weather is less common in the tropics. We tested the generality of this pattern by characterizing the critical temperature minimum (CTMin), hardening, and acclimation responses of túngara frogs (Engystomops pustulosus). These frogs belong to a family with unknown thermal ecology. They are found in a tropical habitat with a highly constant temperature regime. The CTMin of the tadpoles was on average 12.5°C. Pre-metamorphic tadpoles hardened by 1.18°C, while metamorphic tadpoles hardened by 0.36°C. When raised at 21°C, tadpoles acclimated expanding their cold tolerance by 1.3°C in relation to larvae raised at 28°C. These results indicate that the túngara frog has a greatly reduced cold tolerance when compared to species from temperate climates, but it responds to cold temperatures with hardening and acclimation comparable to those of temperate-zone species. Cold tolerance increased with body length but cold hardening was more extensive in pre-metamorphic tadpoles than in metamorphic ones. This study shows that lack of acclimation ability is not general to the physiology of tropical anurans.

Response of Chrysoperla nipponensis (Okamoto) (Neuroptera: Chrysopidae) Under Long and Short Photoperiods.

Photoperiod is an important factor influencing many biological processes including population dynamics of many insect species in temperate zones. To determine the population response of Chrysoperla nipponensis under altered conditions (high temperature and short photoperiod) and to test whether the short photoperiod was suitable for artificial storage, the life table data of C. nipponensis were collected at 25 °C under a long photoperiod, 15:9 h (L:D), and a short photoperiod, 9:15 h (L:D) and analyzed using the age-stage, two-sex life table approach. We found that C. nipponensis developed faster under the long photoperiod than under the short photoperiod. The shorter developmental time, higher fecundity, and higher proportion of females found during the long photoperiod resulted in higher intrinsic and net reproductive rates, but a shorter mean generation time and life expectancy compared to those reared during the short photoperiod. Individuals reared under the short photoperiod also had a high reproductive value. Population projection demonstrated that C. nipponensis reared at the long photoperiod would complete four generations in 150 d, while reared under the short photoperiod would just be entering the second generation. Our results demonstrated that the different fitness values obtained for C. nipponensis individuals by varying photoperiod lengths, were readily distinguishable when using the age-stage, two-sex life table. High winter temperatures would be detrimental to a diapausing population, and diapause induced by the short photoperiod would be beneficial to the storage of natural enemies.

Tropical anurans mature early and die young: Evidence from eight Afromontane Hyperolius species and a meta-analysis.

Age- and size-related life-history traits of anuran amphibians are thought to vary systematically with latitude and altitude. Because the available data base is strongly biased towards temperate-zone species, we provide new estimates on eight afrotropical Reed Frog species. A meta-analysis of the demographic traits in 44 tropical anuran species aims to test for the predicted clinal variation and to contrast results with variation detected in temperate-zone species. The small-sized reed frogs reach sexual maturity during the first or second year of life, but longevity does not exceed three to four years. Latitudinal effects on demographic life-history traits are not detectable in tropical anurans, and altitudinal effects are limited to a slight size reduction at higher elevations. Common features of anuran life-history in the tropics are early sexual maturation at small size and low longevity resulting in low lifetime fecundity. This pattern contrasts with that found in temperate-zone anurans which mature later at larger size and grow considerably older yielding greater lifetime fecundity than in the tropics. Latitudinal and altitudinal contraction of the yearly activity period shape the evolution of life-history traits in the temperate region, while trait variation in the tropics seems to be driven by distinct, not yet identified selective forces.

Hypericum spp. volatile profiling and the potential significance in the quality control of new valuable raw material

The genus Hypericum (Guttiferae) is one of the most representative species in temperate zones and Turkey is one of the most important Mediterranean sites. Due to the increasing commercial value of Hyperici herba (Hypericum perforatum), many wild Turkish Hypericum species have received currently a considerable renewed interest as potential substitutes of the well-established H. perforatum crops for their similar content in the standardization bioactives (hypericins, hyperforins, and flavonoids). The present paper reported the volatile fingerprints of three selected wild Turkish Hypericum species recently characterized as H. perforatum bioactive-like profiles but lacking of the requested well-established usage in the EU market. In this context, the volatile constituents of the three-selected Hypericum spp. were investigated as additional discriminating markers to enhance the likelihood that this adulterating plant raw material will be detected before it is incorporated into finished H. perforatum products.

Comparison of Different Methods for RNA Extraction from Floral Buds of Tree Peony (Paeonia suffruticosa Andr.)

Tree peony (Paeonia suffruticosa Andr.), a species native to China, is one of the most important ornamental and medicinal plants. Like other tree species in temperate and boreal zones, the dormancy-activity transition of floral buds is critical for blooming time and fruit production. However, floral buds contain high levels of secondary metabolites, making the isolation of high quality RNA difficult. To obtain a method suitable for extracting RNA from floral buds of tree peony, we evaluated five different methods, including the cetyltrimethylammonium bromide (CTAB) and Sodium dodecyl sulfate (SDS)-based methods, a modified SDS-TRNzol protocol, and two commercial kits (TRNzol and Qiagen RNeasy Plant Mini Kit). The modified SDS-TRNzol method was capable of efficiently removing polyphenols and other metabolites in floral buds. The isolated RNA was of high purity and integrity, as demonstrated by the the A260/280 ratio of approximately 2.0, and RIN values of more than 9.0. Gel electrophoresis analysis indicated that the extracted RNA had clear 28S and 18S ribosomal RNA bands without DNA contamination. The RNA isolated by this protocol was successfully used for downstream manipulations, such as RT-PCR, RACE, and real-time PCR. Together, the modified SDS-TRNzol protocol is an easy, efficient, and highly reproducible method for RNA isolation from floral buds rich in secondary metabolites.

Juvenile hormone titers, ovarian status and epicuticular hydrocarbons in gynes and workers of the paper wasp Belonogaster longitarsus

The prevailing paradigm for social wasp endocrinology is that of juvenile hormone (JH) functioning pleiotropically in potential and actual queens, where it fuels dominance behaviors, stimulates ovarian growth and/or affects the production of status-linked cuticular compounds. In colonies with annual cycles (e.g., temperate-zone species), female adults produced at the end of the summer (called gynes) are physiologically primed to hibernate. Despite the absence of egg-laying in the pre-overwintering phase, gynes engage in dominance interactions that may affect reproductive potential following hibernation. JH levels have long been inferred to be low in gynes but this has never been tested. In what is the first study to measure JH in gyne-containing colonies of a temperate paper wasp, and the first to incorporate hormone assays in Belonogaster, our results show that the JH titer positively correlates with gyne-specific traits (including oocyte length and a low frequency of foraging trips) in B. longitarsus, a South African paper wasp. Measures of dominance correlated with oocyte length, but not all dominant females possessed activated ovaries. The cuticular hydrocarbon profiles of gynes and workers were distinct, with oocyte length and JH titer showing a positive association with longer-chain methyl-branched alkanes. Nonetheless, evidence for a role of JH in dominance was inconclusive. Finally, the range of JH titers among gynes, and the positive association of JH titers with ovarian status and prospective fertility signals, makes it unlikely that the gyne phenotype is maintained by low JH levels.

Female reproductive cycle and clutch size of Aspidoscelis costata costata (Squamata: Teiidae) from Tonatico, Estado de México

Female reproductive cycle and clutch size are important life history traits in lizards that can be influenced by biotic and/or abiotic factors. Here, the ovarian cycle and clutch size of a high-elevation population (1500–1600m) of Aspidoscelis costata costata in Central Mexico are described. Females were collected monthly between 2005 and 2007, and their reproductive condition was evaluated based on appearance and size of ovarian follicles and presence/absence of oviductal eggs. The reproductive cycle was markedly seasonal with asynchrony in reproductive condition among females. Vitellogenic and gravid females were recorded from April (end of the dry season) through July (middle of the rainy season). Although this population inhabits a semi-humid warm climate, the timing of female reproduction in A. costata costata is similar to the cycle of temperate-zone species of Aspidoscelis. Females produced a single clutch annually with an average clutch size of 7.7±0.44 eggs (median 8 eggs, range 4–14), which is the largest reported to date within the genus Aspidoscelis.

Dislodgement force and shell morphology vary according to wave exposure in a tropical gastropod (Cittarium pica)

ABSTRACTWave exposure has strong influences on population density, morphology and behaviour of intertidal species in temperate zones, but little is known about how intertidal organisms in tropical regions respond to gradients in wave exposure. We tested whether dislodgement force and shell shape of a tropical gastropod, Cittarium pica, differs among shores that vary in wave exposure. After adjusting for body size, we found that C. pica from exposed shores required greater dislodgement force to remove them from the shore, had slightly larger opercula (the closure to the shell aperture), and were slightly squatter in shape (reduced in shell height relative to shell width) than C. pica from sheltered shores. These morphological adjustments are consistent with those observed in temperate gastropods, which are argued to represent adaptive responses to the risk of mortality associated with dislodgement.

Bioluminescence in the ghost fungus Omphalotus nidiformis does not attract potential spore dispersing insects.

Bioluminescence has been known from fungi since ancient times, but little work has been done to establish its potential role. There is evidence that some bioluminescent fungi differentially attract potential spore-dispersing insects, and we aimed to establish if this was the case for the ghost fungus, Omphalotus nidiformis (Agaricales,Marasmiaceae), a widespread Australian temperate zone species. We examined three corroborative lines of evidence: circadian rhythmicity of bioluminescence; field-recorded insect abundance at the time of basidiome production; and attractiveness of glowing fungi to flying insects. Basidiomes glowed continuously day and night, and were present in winter (June-July) when insect abundance was low. To assess attractiveness, we deployed sticky-traps in open woodland in the absence of light pollution, in Treatment (baited with fresh bioluminescent O. nidiformis) and Control pairs, for 480 trap-hours on moonless nights. There was no statistical difference in mean insect abundance between Treatment and Control traps (mean 0.33 and 0.54 individuals per trap night, respectively). To interpret these results, we provide a brief review of competing hypotheses for fungal bioluminescence, and conclude that for some fungi, bioluminescence may be an incidental by-product of metabolism rather than conferring any selective advantage. It is possible that the role of bioluminescence differs among evolutionary lineages of fungi and/or with attributes of their growth environments that could affect spore dispersal, such as wind and insect abundance.