How Do Collaria oleosa and Brachiaria spp. Respond to Increase in Carbon Dioxide Levels?

First Record of Tropical Sod Webworm on Turfgrass in Brazil

Climate change and anthropogenic disturbance in agricultural production systems can facilitate shifts in the distribution of arthropod pest species and in the range of plant hosts on which they feed. This study presents the first record of Tropical Sod Webworm (TSW), Herpetogramma phaeopteralis Guenée (Lepidoptera: Crambidae: Spilomelinae), on native or nativized species of the genus Axonopus (Poaceae) in Brazil. The occurrence of population outbreaks of this species was observed in March and April of 2024 among smallholder cattle farmers in Capão Alto and Campo Belo do Sul, both municipalities situated in the highlands of Santa Catarina State, southern Brazil. The caterpillars feed on leaves during the nocturnal nighttime period, causing extensive defoliation and forming large dry patches of grass. Phylogenetic analyses based on mtCOI support the morphological characterization indicated that the species is H. phaeopteralis. The phylogenetic tree, based on partial sequences of the COI gene, indicated that the Brazilian isolate is more closely related to the Peruvian isolate and is distinct from the American and Japanese isolates. Turfgrass production is an economically important activity in Brazil and, thus, H. phaeopteralis should be monitored to assess its establishment as a primary pest in the landscapes where host plants are employed.

Exposure of insects and host plants to different concentrations of CO2 affects the performance of Mahanarva spectabilis (Hemiptera: Cercopidae) in successive insect generations

The performance of three successive generations of Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) fed on four forages exposed to environments with different CO2 concentrations was evaluated. In the first bioassay, we utilized the following scenarios: A) plants and insects were kept at high and constant CO2 (700 ppm) and B) the insects were kept at CO2 700 ppm and fed on plants from the greenhouse (average of 390 ppm). In the second bioassay, we utilized the following scenarios: C) plants and insects were kept in a greenhouse and D) the insects were kept in the greenhouse and fed on plants kept at CO2 700 ppm. The survival and duration of the nymphal and adult stages and the number of eggs/female of M. spectabilis were evaluated. It was only possible to evaluate the cumulative effects of the increase of CO2 on three successive generations of M. spectabilis kept in a greenhouse, due to the reduced survival of the insects in the first generation in the laboratory. A greater direct than indirect effect of the CO2 level on the performance of M. spectabilis was observed. Furthermore, it should be considered that the effect of CO2 elevation on the survival, periods of development, and fecundity, when taken together, can significantly impact the population dynamics of M. spectabilis in future climate scenarios.

Conventional breeding of insect-resistant crop plants: still the best way to feed the world population

Insect-resistant crops feed much of the world, using reduced carbon inputs and providing much greater economic returns on investment. Newer, more efficient efforts are urgently needed to speed development of insect-resistant plants before a projected 30% global population increase. Plant resistance researchers must employ genotyping by sequencing and high-throughput phenotyping to identify, map and track resistance genes. In contrast to maize, rice, vegetables and wheat, limited progress has occurred to develop meaningful levels of pest resistance in cassava, cowpea and pigeonpea - major sources of nutrition for nearly 1 billion people. A knowledge void exists about the effects of climate change (elevated CO₂) on resistant plants, necessitating efforts to understand this stress. Collaborations with social scientists, extension specialists, economists, spatiotemporal modelers, ecologists, and virologists will be required to develop better ways to integrate insect resistant plants into integrated crop pest management programs.

Navigation in darkness: How the marine midge (Pontomyia oceana) locates hard substrates above the water level to lay eggs

Finding suitable habitats for specific functions such as breeding provides examples of key biotic adaptation. The adult marine midge Pontomyia oceana requires an extremely specific habitat, i.e., hard substrates above water in shallow water, to deposit fertilized eggs. We investigated how these sea surface-skimming insects accomplished this with a stringent time constraint of 1-2 h of the adult life span in the evenings. We observed that in artificial containers, midges aggregated at bright spots only if the light was not in the direction of the sea. This behavior could potentially attract midges toward the shore and away from the open water. Experiments were performed in the intertidal zone in southern Taiwan to test three hypotheses explaining such behavior: gradients of temperature and CO2, and soundscape. No differences were observed in moving directions or aggregation of midges under artificial temperature and CO2 gradients. However, midges preferred sounds at 75 Hz compared with other frequencies (all ≤300 Hz) as observed in a field experiment involving floating traps with loudspeakers. Moreover, when background noise was experimentally masked using white noise of all frequencies, midges were significantly more likely to aggregate at bright spots in the direction of the sea than in the absence of white noise. These results establish that sound is used by midges to navigate in dark seas and move toward the shore where exposed hard substrates are in abundance. Marine mammals present well-known cases of sound pollution at sea; here the finding in the insignificant marine midge is just the harbinger of the potential effects noise at shore may have to affect critical reproductive stages of marine organisms.