Decreased calcium concentration interferes with life history defense strategies of Ceriodaphnia cornuta in response to fish kairomone

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.

Download Full-text

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

PeerJ ◽

10.7717/peerj.10296 ◽

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.

Download Full-text

Inducibility of life history changes by fish kairomone in various developmental stages of Daphnia

Journal of Plankton Research ◽

10.1093/plankt/17.7.1513 ◽

1995 ◽

Vol 17 (7) ◽

pp. 1513-1520 ◽

Cited By ~ 15

Author(s):

Jiřf Macháček

Keyword(s):

Life History ◽

Developmental Stages ◽

Fish Kairomone

Download Full-text

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

10.7287/peerj.preprints.679v1 ◽

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.

Download Full-text

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

Sociobiology ◽

10.13102/sociobiology.v65i1.1786 ◽

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.

Download Full-text

Anti-predation Defense Traits of Daphnia are Associated With the Gut Microbiota Composition Shaped by Fish Kairomone

10.21203/rs.3.rs-757585/v1 ◽

2021 ◽

Author(s):

Qi Liu ◽

Siddiq Akbar ◽

Zihao Ding ◽

Qiming Zhou ◽

Lei Gu ◽

...

Keyword(s):

Life History ◽

Gut Microbiota ◽

Relative Abundance ◽

Life History Traits ◽

Induced Defense ◽

Control Group ◽

Microbiota Composition ◽

Fish Kairomone ◽

Α Diversity ◽

Gut Microbiota Composition

Abstract Background: Gut microbiota plays an important role in host physiology and fitness. The gut microbiota can promote host health by influencing life history traits, especially in arthropods. However, it is not clear whether the performance of host defense traits in response to predator pressure in natural food webs is related to their gut microbiota composition. In this study, we used Daphnia magna as a model organism to investigate the relationship of D. magna life history traits and gut microbiota alterations under predator kairomone based on 16S rRNA amplicon sequencing.Result: We showed that the microbiota composition of D. magna was significantly affected by their predator risk and development stage. The relative abundance of Comamonadaceae (mainly Limnohabitans sp.) significantly decreased in the presence of predator kairomone. Furthermore, the presence of predator kairomone significantly reduced the α diversity of gut microbiota in D. magna with the increase of instar. Among them, the OTUs belonged to Epsilonbacteraeota and Firmicutes in the presence of predator kairomone were significantly higher than those in the control group. The results of functional predictions showed that predation pressure promote the metabolic function of gut microbiota, such as metabolism of energy, cofactors, and vitamins. By analyzing the correlation between the induced defense traits of D. magna and the relative abundance of bacteria, we found that the increased abundance of Comamonadaceae, Moraxellaceae, and Flavobacteriaceae were linearly correlated with the partial defense traits of D. magna. Specifically speaking, body size was positively correlated with an increased abundance of Comamonadaceae, whereas spine length was negatively correlated with an increased abundance of Comamonadaceae but was positively correlated with increased Flavobacteriaceae abundance. Conclusions: Our results suggested that predation risk can affect the composition of the gut microbiota in D. magna, which may indirectly induce the production of defensive traits in D. magna. The results of this study revealed an important role of gut microbiota in the development of defensive traits of Daphnia in response to fish predators. The correlation between microbial abundance and defense traits is of great significance for further understanding the effect of host-microbiota interaction on individual anti-predation defense.

Download Full-text