Article
Ecology
Collin B. Edwards, Stephen P. Ellner, Anurag A. Agrawal
Summary: Plants use multiple traits to defend against herbivores, and the defense synergy hypothesis suggests that some traits are more effective when expressed together. This study tested for synergies between defense traits in common milkweed and found evidence for multiple synergies and antagonisms. The strongest evidence was found between leaf mass per area and low nitrogen content. The study also showed that different defense traits had context-dependent effects on herbivores. These findings provide evidence that multiple classes of plant defense can work together to impact insects.
Article
Ecology
Olivia L. L. Cope, Luke N. N. Zehr, Anurag A. A. Agrawal, William C. C. Wetzel
Summary: Extreme heat events, which are increasing in frequency and intensity, can have varying consequences on insect communities depending on their timing. This study found that the timing of heat waves had multiyear, timing-specific effects on plant-insect communities, with early-season heat waves having more significant and persistent effects than late-season heat waves. The study also showed that heat waves following experimental herbivory had reduced consequences. Overall, the results highlight the complex and lasting ecological effects of extreme climate events, emphasizing the importance of considering timing.
Article
Ecology
Xose Lopez-Goldar, Anurag A. Agrawal
Summary: The nonindependent expression of traits mediating resistance is a major constraint on the evolution of anti-herbivore defense in plants. This study examined genetic correlations among different cardenolide toxins within and between plant tissues and found that concentrations of individual toxins were moderately correlated between tissues. The divergence in cardenolide chemistry between populations was stronger in roots than in leaves and seeds. The study also found tissue and toxin-specific divergent selection on individual toxins, suggesting that the evolution of cardenolides within and between tissues across populations is possible due to their highly independent expression.
Article
Entomology
Kelsey E. Fisher, Steven P. Bradbury
Summary: Habitat loss in the summer breeding range contributes to the decline in the population of eastern North American monarch butterflies, efforts to restore habitat by increasing native plants show promise. Results from an experiment suggest that monarch butterflies tend to fly downwind in resource-devoid environments, yet some individuals also exhibit upwind flight behavior, indicating a potential perceptual range of 125 meters.
ENVIRONMENTAL ENTOMOLOGY
(2021)
Article
Ecology
Samantha M. Knight, D. T. Tyler Flockhart, Rachael Derbyshire, Mark G. Bosco, D. Ryan Norris
Summary: The study suggests that neonicotinoid insecticides may have negative effects on the egg-laying and larval survival of monarch butterflies. Milkweed near neonicotinoid-treated crops is more likely to be preferred by monarch butterflies. However, monarch butterflies do not actively select plots with fewer arthropods for oviposition.
JOURNAL OF ANIMAL ECOLOGY
(2021)
Article
Ecology
Sydney M. Gilmour, Heather M. Kharouba
Summary: Climate change-induced phenological asynchrony between monarch butterflies and milkweed may not negatively affect larval performance, according to a field study in Canada.
ECOLOGY AND EVOLUTION
(2022)
Article
Ecology
M. Popov, D. Prvulovic, J. Sucur, S. Vidovic, N. Samardzic, T. Stojanovic, B. Konstantinovic
Summary: The study showed that water extract of Asclepias syriaca L. exhibited higher antioxidant activity and total tannin content, while the methanol extract had higher antioxidant capacity. The water extract inhibited seed germination in the tested plants but did not inhibit root length, while the methanol extract significantly reduced shoot and root length in all tested plants.
APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH
(2021)
Article
Biology
Nathaniel J. Carlson, Anurag A. Agrawal
Summary: Plant toxicity affects the dietary choices of herbivores, and sequestering herbivores must balance protection from enemies with avoidance of toxicity. Diet mixing can help sequestering herbivores balance nutrition and defense. In this study, large milkweed bugs fed on non-toxic seeds but supplemented their diet with cardenolide-rich milkweed leaf and stem tissues, resulting in reduced growth but enhanced sequestration of defensive toxins.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Article
Plant Sciences
David S. DeLaMater, John J. Couture, Joshua R. Puzey, Harmony J. Dalgleish
Summary: By studying different populations of common milkweed, we found complex interactions between environment, plant traits, and herbivores that can impact monarch larval growth and development. We also found variation within species and geographic distribution resulting in trait changes, which in turn influence monarch larval performance.
AMERICAN JOURNAL OF BOTANY
(2021)
Article
Plant Sciences
Sylvain Pincebourde, Jerome Ngao
Summary: Research shows that leaf age affects leaf gas exchange, with herbivore insects altering these effects. Young leaves maintain steady gas exchange rates after infestation, but as they age, infested leaves show increased photosynthesis, stomatal conductance, and transpiration rates, gradually decreasing thereafter.
FRONTIERS IN PLANT SCIENCE
(2021)
Article
Plant Sciences
Richard J. Knecht, Anshuman Swain, Jacob S. Benner, Steve L. Emma, Naomi E. Pierce, Conrad C. Labandeira
Summary: A trace fossil representing the earliest indication of endophytic feeding behavior has been discovered, dating back to the Middle Pennsylvanian period, approximately 312 million years ago. This finding sheds light on the evolutionary transition to true foliar endophagy and enhances our understanding of early holometabolous insect behaviors and macroevolutionary patterns of plant-insect interactions.
Article
Ecology
Emily K. Mohl, Andrew C. McCall, Madelyn Wood, Lauren Sherman, Mari V. Reid, Patricia A. Saunders, Sara E. Scanga, Clara Danielson, M. Caitlin Fisher-Reid, Heather Marella, Danielle E. Garneau, Kaitlin Stack Whitney, Kendra Cipollini, Jennifer Nesbitt Styrsky, John D. Styrsky, Spencer Rasmussen, Kristine N. Hopfensperger
Summary: Overwintering monarch populations have declined and restoration of milkweeds has become common as a response. This study found that seeds from higher latitudes of Asclepias syriaca germinated faster under all conditions. The research also suggests that latitudinal clines in germination time are more consistent with adaptation to growing season length than spring temperatures.
RESTORATION ECOLOGY
(2023)
Article
Ecology
N. W. Gustafson, J. J. Couture, Harmony J. J. Dalgleish
Summary: Herbivory can directly affect plant fitness by changing reproductive allocation and indirectly affect it by changing pollinator identity or behavior. This study aimed to understand how herbivory severity and plant traits interact to affect insect visitation and pod production in common milkweed. The results showed that increased herbivory severity reduced floral displays, resulting in reduced insect visitation and negative effects on pollination effectiveness.
Article
Forestry
Francesco Martini, I-Fang Sun, Yu-Yun Chen
Summary: Conversion from natural forest to timber plantation can lead to changes in community structure, diversity, and plant-plant and plant-animal interactions. This study found that the total herbivory did not change among forest types, but there were variations in herbivory among different tree species. Leaf damage caused by different feeding guilds was influenced by leaf traits and forest structure. The findings support the resource concentration hypothesis and highlight the importance of leaf traits in mediating the impact of insect feeding guilds on leaf herbivory.
FOREST ECOLOGY AND MANAGEMENT
(2022)
Article
Forestry
Sonia Mediavilla, Montserrat Martinez-Ortega, Santiago Andres, Javier Bobo, Alfonso Escudero
Summary: This study examines the effects of differences in leaf life span on premature losses of leaf area due to insect herbivory and abiotic stress. The results show that tree species with longer leaf duration experience lower area lost to herbivores and less damage due to accelerated senescence during summer drought.
JOURNAL OF FORESTRY RESEARCH
(2022)
