Stink Bug (Hemiptera: Heteroptera: Pentatomidae) Feeding and Phenology on Early-Maturing Soybean in Minnesota.

The invasion by Halyomorpha halys (Stål) and an increasing abundance of native Pentatomidae pose a threat to soybean, Glycine max (L.) Merrill, production in northern states. A risk assessment framework was used to provide an initial assessment of the risk of Pentatomidae affecting soybean production in northern states. A caged field study was performed over two years to assess the response of soybean to H. halys feeding. Cages placed over R4 soybean were infested with 0, 1, 2, 4, or 8 fourth-instar H. halys nymphs per 0.3 row-m, and the insects were allowed to feed for 15 to 16 days. Feeding by H. halys on soybean affected yield components, maturity, and quality (i.e., seed injury). Season-long monitoring of soybean fields was performed via sweep net sampling to assess the likelihood of herbivorous Pentatomidae occurring on soybean during plant growth stages susceptible to feeding injury. Adults of herbivorous species were collected at low densities in fields in mid- to late July before collection of herbivorous nymphs. Herbivorous nymphs were first collected in the R3 and R4 soybean growth stages and their abundance peaked during the R6 soybean growth stage. This preliminary assessment indicates that if populations of exotic and native herbivorous Pentatomidae continue to increase in abundance, they will pose a threat to northern soybean production.

Coral bleaching due to cold stress on a central Red Sea reef flat.

Ocean warming is leading to more frequent coral bleaching events. However, cold stress can also induce bleaching in corals. Here, we report observations of a boreal winter bleaching event in January 2020 in the central Red Sea, mainly within a population of the branching coral Stylophora pistillata on an offshore reef flat. Sea surface temperatures (SSTs) rarely fall below 24°C in this region, but data loggers deployed on several nearby reef flats recorded overnight seawater temperatures as low as 18°C just 3 days before the observations. The low temperatures coincided with an extremely low tide and cool air temperatures, likely resulting in the aerial exposure of the corals during the night time low-tide event. The risk of aerial exposure is rare in winter months, as the Red Sea exhibits seasonal fluctuations in sea level with winter values typically 0.3-0.4 m higher than in summer. These observations are notable for a region typically characterized as a high-temperature sea, and highlight the need for long-term monitoring programs as this rare event may have gone unnoticed.

Stylophora under stress: A review of research trends and impacts of stressors on a model coral species.

Sometimes called the "lab rat" of coral research, Stylophora pistillata (Esper, 1797) has been extensively used in coral biology in studies ranging from reef ecology to coral metabolic processes, and has been used as a model for investigations into molecular and cellular biology. Previously thought to be a common species spanning a wide distribution through the Indo-Pacific region, "S. pistillata" is in fact four genetically distinct lineages (clades) with different evolutionary histories and geographical distributions. Here, we review the studies of stress responses of S. pistillatasensulato (clades 1-4) and highlight research trends and knowledge gaps. We identify 126 studies on stress responses including effects of temperature, acidification, eutrophication, pollutants and other local impacts. We find that most studies have focused on the effect of single stressors, especially increased temperature, and have neglected the combined effects of multiple stressors. Roughly 61% of studies on S. pistillata come from the northern Red Sea (clade 4), at the extreme limit of its current distribution; clades 2 and 3 are virtually unstudied. The overwhelming majority of studies were conducted in laboratory or mesocosm conditions, with field experiments constituting only 2% of studies. We also note that a variety of experimental designs and treatment conditions makes it difficult to draw general conclusions about the effects of particular stressors on S. pistillata. Given those knowledge gaps and limitations in the published research, we suggest a more standardized approach to compare responses across geographically disparate populations and more accurately anticipate responses to predicted future climate conditions.

Size structure of the coral Stylophora pistillata across reef flat zones in the central Red Sea.

Demographic analyses offer insight into the state of a population. Here, we surveyed different reef flat zones (exposed, midreef and sheltered) of six reefs over a cross-shelf gradient to characterize the population structure of Stylophora pistillata, a coral species which dominates reef flats in the central Red Sea. Phototransects were conducted at each reef flat zone, and the density of S. pistillata, the planar area of each colony, and the occurrence of partial mortality were calculated using the program ImageJ. Each colony was also assigned a color morph (yellow, purple or mixed colors). Density and mean size were extremely variable, both among reef flat zones and reefs, but overall, both metrics were lower on the midshelf reefs. The yellow color morph accounted for nearly 90% of colonies surveyed and dominated most reef flats assessed, with the exception of one site where 81% of colonies were purple morphs. There were no spatial trends in the percentage of colonies suffering partial mortality, but overall there is a positive correlation with size class and proportion of colonies with partial mortality. Despite few trends emerging from assessing individual parameters, a PERMANOVA analysis revealed differences among reef flat zones in most of the reefs, highlighting the importance of multivariate analysis. The data presented here serve as a baseline for monitoring and may identify possible future demographic changes to this important coral species in a region increasingly affected by bleaching events.

Physiological and biochemical responses of a coralline alga and a sea urchin to climate change: Implications for herbivory.

Direct responses to rising temperatures and ocean acidification are increasingly well known for many single species, yet recent reviews have highlighted the need for climate change research to consider a broader range of species, how stressors may interact, and how stressors may affect species interactions. The latter point is important in the context of plant-herbivore interactions, as increasing evidence shows that increasing seawater temperature and/or acidification can alter algal traits that dictate their susceptibility to herbivores, and subsequently, community and ecosystem properties. To better understand how marine rocky shore environments will be affected by a changing ocean, in the present study we investigated the direct effects of short-term, co-occurring increased temperature and ocean acidification on a coralline alga (Jania rubens) and a sea urchin herbivore (Echinometra lucunter) and assessed the indirect effects of these factors on the algal-herbivore interaction. A 21-day mesocosm experiment was conducted with both algae and sea urchins exposed to ambient (24 °C, Low CO2), high-temperature (28 °C, Low CO2), acidified (24 °C, High CO2), or high-temperature plus acidified (28 °C, High CO2) conditions. Algal photosynthesis, respiration, and phenolic content were unaffected by increased temperature and CO2, but calcium carbonate content was reduced under high CO2 treatments in both temperatures, while total sugar content of the algae was reduced under acidified, lower temperature conditions. Metabolic rates of the sea urchin were elevated in the lower temperature, high CO2 treatment, and feeding assays showed that consumption rates also increased in this treatment. Despite some changes to algal chemical composition, it appears that at least under short-term exposure to climate change conditions, direct effects on herbivore metabolism dictated herbivory rates, while indirect effects caused by changes in algal palatability seemed to be of minor importance.