Linking Immune Patterns and Life History Shows Two Distinct Defense Strategies in Land Snails (Gastropoda, Pulmonata)

2013 ◽  
Vol 86 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Jacqueline Russo ◽  
Luc Madec
Keyword(s):  
Life History ◽  
Land Snails ◽  
Defense Strategies

scholarly journals Sex-specific predation risk and the evolution of sexual dimorphism in immunocompetence: a theoretical analysis

2014 ◽  
Author(s):  
Benjamin Fanson ◽  
Eirik Søvik
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Sexual Dimorphism ◽  
Immune Function ◽  
Predation Risk ◽  
Reproductive Effort ◽  
Life History Strategies ◽  
Defense Strategies ◽  
Differential Predation ◽  
Predation Costs

Sexual dimorphism in immunocompetence, with males having lower immune function, is a prevalent pattern in nature. The main evolutionary explanation for this pattern is that males preferentially allocate resources away from immune function and towards reproductive effort to increase their competitiveness for limited females. However, the role of differential predation risk between the sexes has not been considered, despite predation risk being a major driver of life history strategies and male sexual traits often having associated predation costs. It is unclear whether increased predation risk should increase or decrease investment in immune function, as males have been shown to utilize both behavioural (e.g. decrease foraging activity) and/or life-history (e.g. decrease investment in sexual trait) defense strategies to manage predation risk. Here, we modelled optimal resource acquisition and allocation towards immune function under differential predation risk with multiple defense strategies. If males have limited defense strategies, increasing predation risk caused males to trade-off immune function for reproductive effort, leading to reduced immunocompetence. In contrast, if males can only decrease predation risk through reduction of reproductive effort (e.g. decrease colouration or calling rates), then increasing predation risk causes immune function to increase. If males can utilize multiple defense strategies and sexual selection is low, then males maintain a constant immune function as predation risk increases. Sexual selection robustly resulted in decreased immunocompetence. Overall, our results suggest that predation plays an important role in the evolution of sexual dimorphism in immunocompetence, but predicting its effect requires understanding the integrated defense strategies available.

scholarly journals Clonal versus non-clonal milkweeds (Asclepias spp.) respond differently to stem damage, affecting oviposition by monarch butterflies

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10296
Author(s):  
Elise He ◽  
Anurag A. Agrawal
Keyword(s):  
Life History ◽  
Induced Defense ◽  
Egg Laying ◽  
Larval Performance ◽  
Monarch Butterflies ◽  
Leaf Quality ◽  
Defense Strategies ◽  
Plant Damage ◽  
And Control ◽  
Clonal Species

Background Oviposition decisions are critical to the fitness of herbivorous insects and are often impacted by the availability and condition of host plants. Monarch butterflies (Danaus plexippus) rely on milkweeds (Asclepias spp.) for egg-laying and as food for larvae. Previous work has shown that monarchs prefer to oviposit on recently regrown plant tissues (after removal of above-ground biomass) while larvae grow poorly on plants previously damaged by insects. We hypothesized that these effects may depend on the life-history strategy of plants, as clonal and non-clonal milkweed species differ in resource allocation and defense strategies. Methodology/Principal Findings We first confirmed butterfly preference for regrown tissue in a field survey of paired mowed and unmowed plots of the common milkweed A. syriaca. We then experimentally studied the effects of plant damage (comparing undamaged controls to plants clipped and regrown, or damaged by insects) on oviposition choice, larval performance, and leaf quality of two closely related clonal and non-clonal species pairs: (1) A. syriaca and A. tuberosa, and (2) A. verticillata and A. incarnata. Clonal and non-clonal species displayed different responses to plant damage, impacting the proportions of eggs laid on plants. Clonal species had similar mean proportions of eggs on regrown and control plants (≈35–40% each), but fewer on insect-damaged plants (≈20%). Meanwhile non-clonal species had similar oviposition on insect-damaged and control plants (20–30% each) but more eggs on regrown plants (40–60%). Trait analyses showed reduced defenses in regrown plants and we found some evidence, although variable, for negative effects of insect damage on subsequent larval performance. Conclusions/Significance Overall, non-clonal species are more susceptible and preferred by monarch butterflies following clipping, while clonal species show tolerance to clipping and induced defense to insect herbivory. These results have implications for monarch conservation strategies that involve milkweed habitat management by mowing. More generally, plant life-history may mediate growth and defense strategies, explaining species-level variation in responses to different types of damage.

scholarly journals LIFE HISTORY TRAITS OF THE PERFORATE DOME SNAIL, VENTRIDENS DEMISSUS (BINNEY, 1843) (GASTROPODA: ZONITIDAE), FROM SEABROOK, TEXAS

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Adrian A. Medellin ◽  
Russell L. Minton
Keyword(s):  
Life History ◽  
Reproductive Behavior ◽  
Conservation Status ◽  
The United States ◽  
Land Snail ◽  
Land Snails ◽  
Snail Species ◽  
Single Pair ◽  
Gut Microbes ◽  
Distribution Ranges

Abstract Ventridens demissus is one of over 2,000 species of land snail in the United States and Canada. Like other zonitid snails, the species is small (10 mm in width) with a thin shell; its distribution ranges from the Appalachians to the southwestern Gulf Coast. Like many land snails, little is known about the biology of V. demissus, and its conservation status remains unstudied. Using a population from Seabrook, Texas, the morphology, reproductive behavior, and gut microbes of V. demissus were described in order to broaden the understanding of this land snail species' life history. Shell morphology data were consistent with those reported previously, while the mean shell required 4.6 N to crush. Reproductive behavior was witnessed between a single pair of individuals, who simultaneously probed one another with their dart apparatuses. In the laboratory, V. demissus laid over 300 small (1.5 mm) eggs, and the growth of twenty hatchlings was followed for at least ten weeks. Gut microbes were dominated by Mycoplasma, Paenibacillus, and enteric groups. These data fill in existing gaps regarding the biology of V. demissus. Future studies on the species should include additional populations from across its range, controlled breeding and rearing experiments, and finer-scaled microbial analysis to distinguish between natural gut flora and ingested microbes.

scholarly journals Sex-specific predation risk and the evolution of sexual dimorphism in immunocompetence: a theoretical analysis

2014 ◽  
Author(s):  
Benjamin Fanson ◽  
Eirik Søvik
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Sexual Dimorphism ◽  
Immune Function ◽  
Predation Risk ◽  
Reproductive Effort ◽  
Life History Strategies ◽  
Defense Strategies ◽  
Differential Predation ◽  
Predation Costs

Sexual dimorphism in immunocompetence, with males having lower immune function, is a prevalent pattern in nature. The main evolutionary explanation for this pattern is that males preferentially allocate resources away from immune function and towards reproductive effort to increase their competitiveness for limited females. However, the role of differential predation risk between the sexes has not been considered, despite predation risk being a major driver of life history strategies and male sexual traits often having associated predation costs. It is unclear whether increased predation risk should increase or decrease investment in immune function, as males have been shown to utilize both behavioural (e.g. decrease foraging activity) and/or life-history (e.g. decrease investment in sexual trait) defense strategies to manage predation risk. Here, we modelled optimal resource acquisition and allocation towards immune function under differential predation risk with multiple defense strategies. If males have limited defense strategies, increasing predation risk caused males to trade-off immune function for reproductive effort, leading to reduced immunocompetence. In contrast, if males can only decrease predation risk through reduction of reproductive effort (e.g. decrease colouration or calling rates), then increasing predation risk causes immune function to increase. If males can utilize multiple defense strategies and sexual selection is low, then males maintain a constant immune function as predation risk increases. Sexual selection robustly resulted in decreased immunocompetence. Overall, our results suggest that predation plays an important role in the evolution of sexual dimorphism in immunocompetence, but predicting its effect requires understanding the integrated defense strategies available.

The scaling of growth, reproduction and defense in colonies of Amazonian Termites

Sociobiology ◽  
2018 ◽  
Vol 65 (1) ◽  
pp. 1
Author(s):  
Pedro A. C. L. Pequeno ◽  
Elizabeth Franklin
Keyword(s):  
Life History ◽  
Social Evolution ◽  
Life History Evolution ◽  
Resource Limitation ◽  
Colony Growth ◽  
Common Species ◽  
Defense Strategies ◽  
Eusocial Insects ◽  
Caste Ratio ◽  
Allocation Strategies

Phenotypes can evolve through life-history tradeoffs. Termites have been the first eusocial insects on Earth, prompting life history evolution at the colony level. Despite this, termite life-history allocation strategies are poorly known. Here, we addressed this issue using novel data on three common species from the diverse, yet understudied Amazonian termite fauna: Neocapritermes braziliensis, Labiotermes labralis and Anoplotermes banksi. Using Oster and Wilson’s optimal caste ratio theory and Higashi et al.’s termite caste allocation theory as frameworks, we assessed how termite colonies should invest in growth (immatures), reproduction (alates) and defense (soldiers) as they accumulate workers. We also examined whether soldier loss in soil-feeding Apicotermitinae (A. banksi) may have affected allocation strategies. We found that: (1) the scaling of immature number was isometric in the three species, contrary to the leveling off expected under resource limitation; (2) colonies of all sizes were equally likely to produce any number of alates, rather than having a size threshold for reproduction; (3) the scaling of soldier number was unrelated to alate production, but varied from isometry in N. braziliensis to negative allometry in L. labralis despite their similar defense strategies; (4) A. banksi had more immatures per worker and a higher maximum alate number per worker than the other species, suggesting that soldier loss may have allowed higher relative investment in colony growth and, possibly, reproduction. Termites can provide novel insights into life-history allocation strategies and their relation to social evolution, and should be better incorporated into sociobiological theory.

scholarly journals Size-dependent shell growth and survival in natural populations of the rock-dwelling land snail Chondrina clienta

2015 ◽  
Vol 93 (5) ◽  
pp. 403-410 ◽  
Author(s):  
Dénes Schmera ◽  
Anette Baur ◽  
Bruno Baur
Keyword(s):  
Life History ◽  
Current Knowledge ◽  
Shell Growth ◽  
Shell Height ◽  
Survival Rates ◽  
Natural Populations ◽  
Land Snails ◽  
Snail Species ◽  
Size Dependent ◽  
History Of

Rock-dwelling land snails, feeding on algae and lichens that grow on stone surfaces, may influence the structure and function of these ecosystems. Yet, little is known about the life history of rock-dwelling snails. We performed a 30-month mark–release–resight study in four populations of Chondrina clienta (Westerlund, 1883) inhabiting vertical walls of abandoned limestone quarries on the Baltic island of Öland, Sweden, to assess growth rate and survival of juvenile snails and determine age at maturity. We marked 800 individuals ranging in shell height from 1.4 to 4.9 mm, released them in their original habitat, and remeasured their shell height at intervals of 6 months. Shell growth of juvenile C. clienta was affected by the site (quarry wall) and the size of the individual, being highest in medium-sized snails. Shell growth occurred during both summer and winter. Annual apparent survival rates of C. clienta were size-dependent and ranged from 58.6% to 96.3%. Sexual maturity was reached at an age of 5 years, which is later than in most large snail species. Our study extends current knowledge on life history of land snails to a rarely studied group dwelling on rock surfaces.

Seasonally contrasting life-history strategies in the land snail Cornu aspersum: physiological and ecological implications

2010 ◽  
Vol 88 (10) ◽  
pp. 995-1002 ◽  
Author(s):  
A. Nicolai ◽  
J. Filser ◽  
V. Briand ◽  
M. Charrier
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Reproductive Strategies ◽  
Energy Content ◽  
Reproductive Traits ◽  
Land Snails ◽  
Life History Strategies ◽  
Hatching Rate ◽  
Trade Offs ◽  
Cornu Aspersum

When a life history is characterized by both seasonality in reproduction and seasonality in offspring fitness, trade-offs in reproductive traits might be adjustments to seasonal time constraints to optimize reproductive success. Therefore, we compared in the laboratory the trade-offs in reproductive traits between early (after maturity) and delayed (after dormancy) reproduction in young land snails Cornu aspersum (Müller, 1774) (syn. Helix aspersa ), depending on food energy content. We also investigated the maternal investment in reproductive output in both breeding periods. After attaining maturity, snails produced single clutches with many small eggs, which resulted, in contrast to previous studies, in large offspring with a low hatching rate owing to high within-clutch cannibalism. The young cannibals may have a higher survival probability in the following hibernation. Snails starting to reproduce after hibernation had smaller clutches of larger eggs, resulting in high quantity of lighter offspring. The clutch mass was positively correlated with maternal mass in snails reproducing after having attained maturity and negatively correlated in snails reproducing after hibernation. Multiple oviposition occurred only after hibernation, thereby enhancing reproductive success. An energy-rich diet did not affect reproductive strategies. Further studies should focus on seasonal plasticity of reproductive strategies in natural populations of C. aspersum and investigate survival probabilities of breeders and juveniles in an evolutionary context.

Interrelationships of factors of social development are more complex than Life History Theory predicts

2019 ◽  
Vol 42 ◽  
Author(s):  
Boris Kotchoubey
Keyword(s):  
Life History ◽  
Social Development ◽  
Life History Theory ◽  
Strong Correlations ◽  
Behavioral Features

Abstract Life History Theory (LHT) predicts a monotonous relationship between affluence and the rate of innovations and strong correlations within a cluster of behavioral features. Although both predictions can be true in specific cases, they are incorrect in general. Therefore, the author's explanations may be right, but they do not prove LHT and cannot be generalized to other apparently similar processes.

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