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1. Data from: Live fast, die young? Day- and night-warming affects the growth, survivorship and behavior of caterpillars in the field

   https://doi.org/10.5061/dryad.n8pk0p35s  

   Yang, Louie; Postema, Elizabeth; Arefaine, Heran; Cohoon, Fernanda; Deen, Emma; Durand, Yvonne; Erdosh, Gwendolyn; Ma, Hailey; Mausling, Courtney; Solís, Sarah; et al (January 2025, Dryad)

   While both daytime and nighttime temperatures are increasing with climate change, few studies have experimentally investigated their differential effects under field conditions. We conducted a factorial field experiment examining how day- and night-warming impact the growth, survivorship, and behavior of cabbage white caterpillars (Pieris rapae). In this experiment, the night-warming only treatment showed the highest rates of caterpillar growth, but also showed the highest mortality, the shortest maximum caterpillar lengths, the least accumulated herbivory and reduced pupation. Caterpillars in the treatments that were not warmed during the day showed daytime-shifted growth, and caterpillars in the combined day- and night-warming treatment showed strongly night-shifted herbivory. Both biotic (e.g., predation risk) and abiotic (e.g., thermal) factors could have contributed to these results. Broadly, these results show the importance of temperature-mediated behavioral changes in diel activity for caterpillar development and survival. These results also support the emerging hypotheses that periods of reduced activity may be important for successful development, that warmer nighttime conditions could limit a temporal thermal refuge for caterpillars, and that increasing temperatures could increase the likelihood of metabolic meltdown. By documenting organismal responses in the context of more complex microclimates and communities, this experiment also illustrates the value of field studies to provide insights into how ectotherms might respond to ongoing climate change. 

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2. The interactive effects of heat stress, parasitism and host plant quality in a host–parasitoid system

   https://doi.org/10.1111/1365-2435.14498  

   Parker, Anna L.; Kingsolver, Joel G. (January 2024, Functional Ecology)

   Abstract Species interactions are expected to change in myriad ways as the frequency and magnitude of extreme temperature events increase with anthropogenic climate change.The relationships between endosymbionts, parasites and their hosts are particularly sensitive to thermal stress, which can have cascading effects on other trophic levels.We investigate the interactive effects of heat stress and parasitism on a terrestrial tritrophic system consisting of two host plants (one common, high‐quality plant and one novel, low‐quality plant), a caterpillar herbivore and a specialist parasitoid wasp.We used a fully factorial experiment to determine the bottom‐up effects of the novel host plant on both the caterpillars' life history traits and the wasps' survival, and the top‐down effects of parasitism and heat shock on caterpillar developmental outcomes and herbivory levels.Host plant identity interacted with thermal stress to affect wasp success, with wasps performing better on the low‐quality host plant under constant temperatures but worse under heat‐shock conditions.Surprisingly, caterpillars consumed less leaf material from the low‐quality host plant to reach the same final mass across developmental outcomes.In parasitized caterpillars, heat shock reduced parasitoid survival and increased both caterpillar final mass and development time on both host plants.These findings highlight the importance of studying community‐level responses to climate change from a holistic and integrative perspective and provide insight into potential substantial interactions between thermal stress and diet quality in plant–insect systems. Read the freePlain Language Summaryfor this article on the Journal blog. 

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3. Experimental warming across a tropical forest canopy height gradient reveals minimal photosynthetic and respiratory acclimation

   https://doi.org/10.1111/pce.14134  

   Carter, Kelsey R.; Wood, Tana E.; Reed, Sasha C.; Butts, Kaylie M.; Cavaleri, Molly A. (July 2021, Plant, Cell & Environment)

   Abstract Tropical forest canopies cycle vast amounts of carbon, yet we still have a limited understanding of how these critical ecosystems will respond to climate warming. We implemented in situ leaf‐level + 3°C experimental warming from the understory to the upper canopy of two Puerto Rican tropical tree species,Guarea guidoniaandOcotea sintenisii. After approximately 1 month of continuous warming, we assessed adjustments in photosynthesis, chlorophyll fluorescence, stomatal conductance, leaf traits and foliar respiration. Warming did not alter net photosynthetic temperature response for either species; however, the optimum temperature ofOcoteaunderstory leaf photosynthetic electron transport shifted upward. There was noOcotearespiratory treatment effect, whileGuarearespiratory temperature sensitivity (Q₁₀) was down‐regulated in heated leaves. The optimum temperatures for photosynthesis (T_opt) decreased 3–5°C from understory to the highest canopy position, perhaps due to upper canopy stomatal conductance limitations.Guareaupper canopyT_optwas similar to the mean daytime temperatures, whileOcoteacanopy leaves often operated aboveT_opt. With minimal acclimation to warmer temperatures in the upper canopy, further warming could put these forests at risk of reduced CO₂uptake, which could weaken the overall carbon sink strength of this tropical forest. 

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4. The Dangers of Growing Old: Adult Moths Face Higher Predation Pressures than Caterpillars in Hyles lineata

   https://doi.org/10.3390/insects16040347  

   Sanchez, Braulio A; Da_Cunha, Oceane; Savage, Jackson W; Horne, L Miles; Saenz-Arreola, Sol; Pollard, Kajaya; Neria, Oliver; Duffendack, Spencer; Terrazas, Simon; Diaz, Javier M; et al (April 2025, Insects)

   Holometabolous insects display drastically different morphologies across life stages (i.e., larvae vs. adults). Morphological differences across life stages, such as different sizes and coloration, likely result in differential survival, as predators may find individuals of one life stage more conspicuous and/or more energetically profitable than another. Furthermore, prey conspicuousness may vary temporally because both the sensory environment and predator sensory abilities differ between day and night. Here, we investigated how the interaction between life stage (caterpillar vs. moth) and time of day (day vs. night) influences predation of the white-lined sphinx (Lepidoptera: Hyles lineata). We predicted that caterpillars would be less susceptible to predation than adult moths, as adults are larger and have a more conspicuous shape. After quantifying predation for 72 h during dawn and dusk using 199 plasticine replicas each of adults and caterpillars, predation on adult replicas was twice that of predation on caterpillar replicas. Furthermore, replicas were six times more likely to be predated on during the day than during the night. Lastly, attacks were made mainly by birds, which carried out 86% of the attacks on adult models and 85% of those on caterpillar models. These data support the hypothesis that predation rates differ across life stages in holometabolous insects. This research lays a foundation for further investigation into how specific differences in morphology across life stages affect predation and survival in holometabolous insects. 

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5. Top-down effects from parasitoids may mediate plant defence and plant fitness

   https://doi.org/DOI: 10.1111/1365-2435.13617  

   Tan, C.-W.; Peiffer, Michelle; Ali, Jared G.; Luthe, D.S.; Felton, Gary w. (October 2020, Functional ecology)

   null (Ed.)

   1. Plants face many environmental stresses that can impact their survival, development and fitness. Insects are the most diverse, abundant and threatening herbivores in nature. As a consequence, plants produce direct chemical and physical defences to reduce herbivory. They also release volatiles to recruit natural enemies that indirectly protect them from herbivory. The recruitment of parasitic wasps can benefit plant fitness because they ultimately kill their insect hosts. 2. Recently, studies showed that parasitoids can indirectly mediate plant defences by modulating herbivore oral secretions. In addition to the direct benefits of parasitoids in terms of reducing herbivore survival, we tested if the reduction in induced defences by parasitized caterpillars compared to non-parasitized caterpillars may reduce the costs associated with defence expression. 3. We provide evidence that tomato plants treated with saliva from parasitized caterpillars have significantly higher fitness parameters including increased flower numbers (16.3%) and heavier fruit weight (13.5%), compared to plants treated with saliva from non-parasitized caterpillars. Since plants were grown without actual herbivores, the higher values for these fitness parameters were due to lower costs of induced defences and not due to reduced herbivory by parasitized caterpillars. Furthermore, the resulting seed germination time was shorter and the germination rate was higher when the maternal plants were previously exposed to parasitized herbivore treatment compared to control (non-treated) plants. 4. Overall, application of saliva did not result in transgenerational priming of offspring defence responses. However, offspring of parents exposed to caterpillar saliva had lower constitutive levels and higher induced levels of trypsin inhibitor than offspring from unexposed parents. 5. This study shows that the saliva of parasitized caterpillars can modulate plant defences and further demonstrates that the lower induction of plant defences is associated with elevated plant fitness in the absence of herbivore feeding, suggesting that induced plant defences are costly. 

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