Abiotic conditions rather than resource availability cues determine aerial dispersal behaviour in spiderlings of Dolomedes triton (Araneae: Pisauridae)

2013 ◽  
Vol 145 (1) ◽  
pp. 29-39
Author(s):  
Carol M. Frost ◽  
Alice K. Graham ◽  
John R. Spence
Keyword(s):  
Food Availability ◽  
Resource Competition ◽  
Abiotic Factors ◽  
Food Limitation ◽  
Dispersal Behaviour ◽  
Abiotic Conditions ◽  
Aerial Dispersal ◽  
Conspecific Density ◽  
High Dispersal ◽  
Dolomedes Triton

AbstractMany species respond to risks and benefits of dispersal that vary over the short term through condition-dependent dispersal. We used wind tunnels to investigate how abiotic factors, spiderling age, and indicators of environmental quality affect aerial dispersal behaviour of spiderlings in Dolomedes triton (Walckenaer) (Araneae: Pisauridae), a denizen of temporary habitats. More than half of all spiderlings exhibited preballooning, ballooning, or spanning behaviours. Warm temperatures (>22.5 °C) and low wind speeds (<2.0 m/second) increased aerial dispersal. Aerial dispersal behaviour increased significantly until 5 days after hatch, after which it decreased, coinciding with the onset of active hunting by spiderlings. In contrast, cues about ambient food availability (egg sac number and food limitation of the mother) and potential resource competition or risk of cannibalism (conspecific density) did not affect aerial dispersal propensity. Offspring from different females ballooned in different proportions, except at the peak of dispersal, but a female's reproductive output and propensity of her offspring to balloon were uncorrelated. Thus, it appears that spiderlings of D. triton adopt a fixed strategy of high dispersal rate under optimal abiotic conditions, rather than reducing dispersal in response to cues about local food availability or conspecific density.

scholarly journals Non-breeding season habitat quality mediates the strength of density-dependence for a migratory bird

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150624 ◽  
Author(s):  
Peter P. Marra ◽  
Colin E. Studds ◽  
Scott Wilson ◽  
T. Scott Sillett ◽  
Thomas W. Sherry ◽  
...  
Keyword(s):  
Habitat Quality ◽  
Body Condition ◽  
Resource Competition ◽  
Food Limitation ◽  
Natural Populations ◽  
Migratory Bird ◽  
Breeding Period ◽  
Mangrove Habitat ◽  
Long Distance ◽  
Conspecific Density

Our understanding of when natural populations are regulated during their annual cycle is limited, particularly for migratory species. This information is needed for parametrizing models that can inform management and conservation. Here, we use 14 years of data on colour-marked birds to investigate how conspecific density and habitat quality during the tropical non-breeding period interact to affect body condition and apparent annual survival of a long-distance migratory songbird, the American redstart ( Setophaga ruticilla ). Body condition and survival of birds in high-quality mangrove habitat declined as density increased. By contrast, body condition improved and survival did not vary as density increased in adjacent, lower quality scrub habitat, although mean condition and survival were almost always lower than in mangrove. High rainfall enhanced body condition in scrub but not in mangrove, suggesting factors such as food availability outweighed consequences of crowding in lower quality habitat. Thus, survival of overwintering redstarts in mangrove habitat, disproportionately males, appears to be regulated by a crowding mechanism based on density-dependent resource competition. Survival of individuals in scrub, mostly females, appears to be limited by density-independent environmental factors but not regulated by crowding. The contrasting effects of density and food limitation on individuals overwintering in adjacent habitats illustrate the complexity of processes operating during the non-breeding period for migratory animals, and emphasize the need for long-term studies of animals in multiple habitats and throughout their annual cycles.

Coral husbandry for ocean futures: leveraging abiotic factors to increase survivorship, growth, and resilience in juvenile Montipora capitata

2021 ◽  
Vol 657 ◽  
pp. 123-133
Author(s):  
JR Hancock ◽  
AR Barrows ◽  
TC Roome ◽  
AS Huffmyer ◽  
SB Matsuda ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Larval Rearing ◽  
Abiotic Conditions ◽  
Montipora Capitata ◽  
Reef Restoration ◽  
Juvenile Corals ◽  
Bleaching Response ◽  
The Face ◽  
Survival And Growth ◽  
Global And Local

Reef restoration via direct outplanting of sexually propagated juvenile corals is a key strategy in preserving coral reef ecosystem function in the face of global and local stressors (e.g. ocean warming). To advance our capacity to scale and maximize the efficiency of restoration initiatives, we examined how abiotic conditions (i.e. larval rearing temperature, substrate condition, light intensity, and flow rate) interact to enhance post-settlement survival and growth of sexually propagated juvenile Montipora capitata. Larvae were reared at 3 temperatures (high: 28.9°C, ambient: 27.2°C, low: 24.5°C) for 72 h during larval development, and were subsequently settled on aragonite plugs conditioned in seawater (1 or 10 wk) and raised in different light and flow regimes. These juvenile corals underwent a natural bleaching event in Kāne‘ohe Bay, O‘ahu, Hawai‘i (USA), in summer 2019, allowing us to opportunistically measure bleaching response in addition to survivorship and growth. This study demonstrates how leveraging light and flow can increase the survivorship and growth of juvenile M. capitata. In contrast, larval preconditioning and substrate conditioning had little overall effect on survivorship, growth, or bleaching response. Importantly, there was no optimal combination of abiotic conditions that maximized survival and growth in addition to bleaching tolerances. This study highlights the ability to tailor sexual reproduction for specific restoration goals by addressing knowledge gaps and incorporating practices that could improve resilience in propagated stocks.

Plasticity in extended phenotypes: how the antlion Myrmeleon crudelis adjusts the pit traps depending on biotic and abiotic conditions

2019 ◽  
Vol 66 (1-2) ◽  
pp. 41-47 ◽  
Author(s):  
Alejandro G. Farji-Brener ◽  
Sabrina Amador-Vargas
Keyword(s):  
Abiotic Factors ◽  
Plant Cover ◽  
Coarse Grained ◽  
Abiotic Conditions ◽  
Fine Grained ◽  
Fine Soil ◽  
Fine Grained Soil ◽  
Trap Size ◽  
Pit Depth ◽  
Pit Design

Abstract The physical structures built by animals are considered extended phenotypes that reflect how organisms make decisions and deal with changes in their biotic and abiotic environment. We summarize the results of several studies on Myrmeleon crudelis, a neuropteran larva that digs pit-traps in the soil to capture small arthropods (mostly ants) in the tropical dry forests of Costa Rica. Specifically, we showed how this species responds to varying biotic and abiotic conditions with changes in the design and/or location of its pit traps. Several experiments and field comparisons indicate that: 1) antlions adjust the pit design according to the abundance and type of prey. When prey is scarce, antlions increased trap diameter, an architectural adjustment that enhances the probability of prey encounter. Antlions that experienced high prey abundance, but the prey easily escaped, then increased pit depth, an adjustment that increases the chance of prey retention; 2) soil compaction strongly reduced pit-trap size and abundance; 3) antlions preferred soils with high proportion of fine-particle size to build pits. In fine-grained soil, pit-traps are larger and more efficient to capture prey than traps in coarse-grained soils; and 4) pit-traps may also be affected through indirect effects of soil structure and vegetation cover. Areas with fine-soil presented less plant cover, and plant cover could be beneficial for antlions because it acts as a shelter against direct sunlight and rainfall, or it may represent a cost because it is a source of leaflitter falling in the pits. The works summarized here how trap-building predators can exhibit considerable flexibility in trap construction in response to various biotic and abiotic factors, emphasizing how the study of extended phenotypes can be a useful approach to better understand the flexibility of foraging behaviors.

Impact of Abiotic Factors on Onion Thrips (Thysanoptera: Thripidae) Aerial Dispersal in an Onion Ecosystem

2016 ◽  
Vol 45 (5) ◽  
pp. 1115-1122 ◽  
Author(s):  
Erik A. Smith ◽  
E. J. Shields ◽  
B. A. Nault
Keyword(s):  
Abiotic Factors ◽  
Onion Thrips ◽  
Aerial Dispersal

scholarly journals Phenological study of congeneric Myrcia species and Clethra scabra in wetland and drained habitats in a Montane Forest

2020 ◽  
Author(s):  
Vinícius Londe ◽  
Jaqueline Alves Pereira ◽  
Hildeberto Caldas de Sousa
Keyword(s):  
Relative Humidity ◽  
Abiotic Factors ◽  
Montane Forest ◽  
The Other ◽  
Maximum Temperature ◽  
Wetland Soil ◽  
Congeneric Species ◽  
Abiotic Conditions ◽  
Local Factors ◽  
The Tropics

Abstract Although important, phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics. Herein, we integrate phylogeny, ecology and biometeorology to verify whether the phenophases of congeneric species Myrcia laruotteana and Myrcia amazonica or Clethra scabra differ when their populations inhabit wetland and drained habitats and to determine what abiotic factors affect the vegetative and reproductive phenophases of these species in distinct habitat patches. We collected data on phenological events of 80 trees for 1 year in Itacolomi State Park, Brazil, and related them to abiotic local factors. Contrary to our expectation, the phenophases of the congeneric species did not differ between habitats, but the reproductive phenophases of C. scabra did and was greater in drained soil. Phenophases of C. scabra were affected by the depth of the water table and maximum temperature in the wetland soil. Insolation, precipitation, maximum temperature and relative humidity influenced Myrcia and Clethra in the drained soil. The differences between C. scabra populations suggest that this species is phenotypically plastic and can present distinct phenophases depending on the habitat it inhabits. On the other hand, the congeneric Myrcia species may have similar phenophases in distinct habitats because of their shared similarities during their evolution. This study provides a better understanding of the ecology of these species and their adaptations to different abiotic conditions. Data of this nature are important in a changing world and can inform strategies for adaptive management.

scholarly journals Experimental food supplementation increases reproductive effort in an antbird in subtropical Brazilian Atlantic Forest fragments

2014 ◽  
Author(s):  
James J Roper ◽  
André M. X. Lima ◽  
Angélica M. K. Uejima
Keyword(s):  
Food Availability ◽  
Reproductive Effort ◽  
Fragment Size ◽  
Food Limitation ◽  
Survival Rates ◽  
Food Supplementation ◽  
Fragmented Landscape ◽  
Forest Fragments ◽  
Daily Nest Survival ◽  
Nesting Patterns

Food limitation may interact with nest predation and influence nesting patterns, such as breeding season length and renesting intervals. If so, reproductive effort should change with food availability. Thus, when food is limited, birds should have fewer attempts and shorter seasons than when food is not limiting. Here we experimentally test that increased food availability results in increased reproductive effort in a fragmented landscape in the Variable Antshrike (Thamnophilus caerulescens) in southern Brazil. We followed nesting pairs in five natural fragments (4, 23, 24, 112, 214 ha) in which food was supplemented for half of those pairs, beginning with the first nest. Nest success in the largest (214 ha) fragment was 59%, compared to 5% in the 112 ha fragment and no nest was successful in the smallest (24 ha) fragment. Birds were seen, but evidence of nesting was never found in the two smallest fragments. Pairs with supplemented food were more likely to increase clutch size from two to three eggs, tended to renest sooner (20 d on average) than control pairs. Also, fragment size interacted with breeding and pairs in the largest fragment had greater daily nest survival rates, and so nests tended to last longer, and so these pairs had fewer nesting attempts than those in the 112 ha fragment while more than those in the smallest fragment with nesting (24 ha). Clearly, pairs increased their reproductive effort when food was supplemented in comparison to control pairs and fragment size seems to influence both predation risk and food abundance.

scholarly journals Population genomics and demographic sampling of the ant-plant Vachellia drepanolobium and its symbiotic ants from sites across its range in East Africa

2018 ◽  
Author(s):  
John H. Boyle ◽  
Dino Martins ◽  
Paul M. Musili ◽  
Naomi E. Pierce
Keyword(s):  
Spatial Distribution ◽  
Genetic Structure ◽  
Host Plants ◽  
Species Coexistence ◽  
Population Genomics ◽  
Abiotic Factors ◽  
Landscape Genomics ◽  
Abiotic Conditions ◽  
Environmental Perturbations ◽  
Insight Into

AbstractThe association between the African ant plant, Vachellia drepanolobium, and the ants that inhabit it has provided insight into the boundaries between mutualism and parasitism, the response of symbioses to environmental perturbations, and the ecology of species coexistence. We use a landscape genomics approach at sites sampled throughout the range of this system in Kenya to investigate the demographics and genetic structure of the different partners in the association. We find that different species of ant associates of V. drepanolobium show striking differences in their spatial distribution throughout Kenya, and these differences are only partly correlated with abiotic factors. A comparison of the population structure of the host plant and its three obligately arboreal ant symbionts, Crematogaster mimosae, Crematogaster nigriceps, and Tetraponera penzigi, shows that the ants exhibit somewhat similar patterns of structure throughout each of their respective ranges, but that this does not correlate in any clear way with the respective genetic structure of the populations of their host plants. A lack of evidence for local coadaptation in this system suggests that all partners have evolved to cope with a wide variety of biotic and abiotic conditions.

scholarly journals Heterogeneity in local density allows a positive evolutionary relationship between self-fertilisation and dispersal

2017 ◽  
Author(s):  
James Rodger ◽  
Pietro Landi ◽  
Cang Hui
Keyword(s):  
Resource Competition ◽  
Local Density ◽  
Evolutionary Relationship ◽  
Negative Relationship ◽  
Theoretical Work ◽  
Extinction Rate ◽  
Range Edge ◽  
High Dispersal ◽  
Baker’S Law ◽  
The Relationship

AbstractTheoretical work predicts that dispersal and self-fertilisation (selfing) should always be negatively correlated and the Good Coloniser Syndrome (GCS) of high dispersal and selfing should not occur when both traits are free to evolve. This contradicts positive relationships between selfing and dispersal in empirical data. Critically, previous work assumes density of adults is spatially and temporally homogeneous, so selfing results in homogeneity in propagule production and competition, which eliminates the benefit of dispersal for escaping from local resource competition. We investigate the joint evolution of dispersal and selfing in a demographically structured metapopulation model where local density varies due to stochastic extinction-recolonisation dynamics. Increasing local extinction rate reduces local density across the metapopulation, which favours high selfing to mitigate mate limitation, but increases heterogeneity in density, which favours high dispersal for escape from competition. Together, these effects produce a positive relationship between selfing and dispersal, and evolution of the GCS. Nevertheless, the relationship between selfing and dispersal is context-dependent, as varying dispersal cost yields a negative relationship. Our results imply that if spatiotemporal heterogeneity in environmental suitability increases towards the range edge, the GCS may evolve there, favouring further range expansion (Cf. Baker’s Law).

scholarly journals Food limitation constrains host immune responses to nematode infections

2016 ◽  
Vol 12 (9) ◽  
pp. 20160471 ◽  
Author(s):  
Kristian M. Forbes ◽  
Tapio Mappes ◽  
Tarja Sironen ◽  
Tomas Strandin ◽  
Peter Stuart ◽  
...  
Keyword(s):  
Immune Responses ◽  
Food Availability ◽  
Food Limitation ◽  
Finite Energy ◽  
Innate Immune ◽  
Food Supplementation ◽  
Boreal Winter ◽  
Intestinal Nematode ◽  
Trade Offs ◽  
Parasite Infections

Trade-offs in the allocation of finite-energy resources among immunological defences and other physiological processes are believed to influence infection risk and disease severity in food-limited wildlife populations. However, this prediction has received little experimental investigation. Here we test the hypothesis that food limitation impairs the ability of wild field voles ( Microtus agrestis ) to mount an immune response against parasite infections. We conducted a replicated experiment on vole populations maintained in large outdoor enclosures during boreal winter, using food supplementation and anthelmintic treatment of intestinal nematodes. Innate immune responses against intestinal parasite infections were compared between food-supplemented and non-supplemented voles. Voles with high food availability mounted stronger immune responses against intestinal nematode infections than food-limited voles. No food effects were seen in immune responses to intracellular coccidian parasites, possibly owing to their ability to avoid activation of innate immune pathways. Our findings demonstrate that food availability constrains vole immune responses against nematode infections, and support the concept that spatio-temporal heterogeneity in food availability creates variation in infectious disease susceptibility.

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