Brown midrib (BMR) and plant age impact fall armyworm (Spodoptera frugiperda) growth and development in sorghum-sudangrass (Sorghum x drummondii).

Economic losses from insect herbivory in agroecosystems has driven the development of integrated pest management strategies that reduce pest incidence and damage; however, traditional chemicals-based control is either being complemented or substituted with sustainable and integrated methods. Major sustainable pest management strategies revolve around improving host plant resistance, and one of these traits of interest is Brown midrib (BMR). Originally developed to increase nutritional value and ease of digestion for animal agriculture, BMR is a recessive plant gene usually found in annual grasses, including sorghum and sorghum-sudangrass hybrids. In sorghum-sudangrass, BMR expressed plants have lower amounts of lignin, which produces a less fibrous, more digestible crop, with possible implications for plant defense against herbivores- an area currently unexplored. Fall Armyworm (FAW; Spodoptera frugiperda) is a ruinous pest posing immense threat for sorghum producers by severely defoliating crops and being present in every plant stage. Using FAW, we tested the effect of seed treatment, BMR, and plant age on FAW growth, development, and plant defense responses in sorghum-sudangrass. Our results show that seed treatment did not affect growth or development, or herbivory. However, presence of BMR significantly reduced pupal mass relative to its non-BMR counterpart, alongside a significant reduction in adult mass. We also found that plant age was a major factor as FAW gained significantly less mass, had longer pupation times, and had lower pupal mass on the oldest plant stage explored, 60-days, compared to younger plants. These findings collectively show that pest management strategies should consider plant age, and that the effects of BMR on plant defenses should also be studied.

PREVALENCE OF EHRLICHIA AND ANAPLASMA SPP. IN TICKS COLLECTED FROM CATTLE AND DEER IN ARKANSAS, USA.

Bovine anaplasmosis, caused by Anaplasma marginale, is widespread in cattle in the southeast United States. The pathogen is biologically transmitted by Dermacentor spp. ticks, and mechanically transmitted by biting flies and via fomites. Despite high reported regional seroprevalence, Dermacentor spp. are rare on cattle in the southeast. To identify other putative An. marginale vectors, and to characterize cattle exposure to other tick-borne pathogens, we collected ticks from Arkansas cattle herds in 2020-2022. Recognizing that deer are important hosts for some of the same tick species that parasitize cattle, we also collected ticks from hunter-killed deer in the fall and winter of 2021. Ticks were screened for bacteria in the family Anaplasmataceae using qPCR. Positive samples were further amplified using a PCR assay targeting the groEL gene, and the resulting amplicons were sequenced for identification. A total of 3,794 ticks were collected, the majority of which were Amblyomma americanum. Amblyomma americanum was the most common species on cattle, and Ixodes scapularis was most common on deer. No ticks were positive for An. marginale, though Anaplasma phagocytophilum was detected in deer-collected I. scapularis, as well as in a single engorged Am. americanum from cattle. Amblyomma americanum from cattle were infected with Ehrlichia ewingii, Ehrilichia chaffeensis, and Panola Mountain Ehrlichia. Cattle in Arkansas are exposed to several ehrlichial pathogens and may also be exposed to An. phagocytophilum. The importance of these pathogens, particularly Panola Mountain Ehrlichia, in causing cattle disease in Arkansas deserves further study, as does the importance of mechanical transmission of An. marginale in bovine anaplasmosis epidemiology.

Wild bees respond differently to sampling traps with vanes of different colors and light reflectivity in a livestock pasture ecosystem.

Wild bees are important pollinators and monitoring their abundance and diversity is necessary to develop conservation protocols. It is imperative to understand differences in sampling efficiency among different trap types to help guide monitoring efforts. This study used a new vane trap design to collect bees in a livestock pasture ecosystem and examined the impact of six different vane colors on wild bee sampling. We recorded 2230 bees comprising 49 species and five families. The most abundant species were Augochlorella aurata (25.8%), Lasioglossum disparile (18.3%), Lasioglossum imitatum (10.85%), Agapostemon texanus (10.8%), Melissodes vernoniae (9.9%) and Halictus ligatus (4.7%). Traps with bright blue vanes captured the greatest number and diversity of bees as compared to traps with bright yellow, dark blue, dark yellow, and purple vanes. Red vanes had the lowest captures rates of individuals and species. Different colors were associated with different bee species arrays and only nine species were found in all vane color types. Vanes with higher light reflectance properties (within 400-600 nm range) attracted the greatest number of bees. These results show that different light wavelengths and reflectivity of vane traps influence bee capture rates, and such findings can help optimize bee sampling methods in different ecosystems.

Collaborating With Community Scientists Across Arkansas to Update Tick Distributions and Pathogen Prevalence of Spotted Fever Group Rickettsia and Ehrlichia.

Tick-borne diseases (TBD) in humans have dramatically increased over recent years and although the bulk of cases are attributable to Lyme Disease in the Northeastern US, TBDs like spotted fever rickettsiosis and ehrlichiosis heavily impact other parts of the country, namely the mid-south. Understanding tick and pathogen distributions and prevalence traditionally requires active surveillance, which quickly becomes logistically and financially unrealistic as the geographic area of focus increases. We report on a community science effort to survey ticks across Arkansas to obtain updated data on tick distributions and prevalence of human tick-borne disease-causing pathogens in the most commonly encountered ticks. During a 20-mo period, Arkansans submitted 9,002 ticks from 71 of the 75 counties in the state. Amblyomma americanum was the most common tick species received, accounting for 76% of total tick submissions. Nearly 6,000 samples were screened for spotted fever group Rickettsia (SFGR) and Ehrlichia, resulting in general prevalence rates of 37.4 and 5.1%, respectively. In addition, 145 ticks (2.5%) were infected with both SFGR and Ehrlichia. Arkansas Department of Health reported 2,281 spotted fever and 380 ehrlichiosis cases during the same period as our tick collections. Since known SFGR vectors Dermacentor variabilis and Amblyomma maculatum were not the most common ticks submitted, nor did they have the highest prevalence rates of SFGR, it appears that other tick species play the primary role in infecting humans with SFGR. Our investigation demonstrated the utility of community science to efficiently and economically survey ticks and identify vector-borne disease risk in Arkansas.

Color of Pan Trap Influences Sampling of Bees in Livestock Pasture Ecosystem.

The decline in insect pollinators has increased the importance of accurately monitoring pollinator diversity and abundance over time. Sampling techniques include the use of passive insect traps such as pan traps, yet there is still discussion over their utility and effectiveness in different ecosystems. The objective was to examine four different colors of pan traps (blue, green, yellow, and purple) for their utility in sampling bees in native forages rotationally grazed by sheep and to compare the relative abundance, richness, similarity, and community assemblage patterns among the four trap colors. Most bees were from the Halictidae family (89%). The most abundant species were Lasioglossum imitatum (42.2%), Augochlorella aurata (8.3%), L. subviridatum (6.8), Agapostemon texanus (6.4), and L. birkmani (4.1%). Blue color traps exhibited the highest rates of bee capture and species accumulation. Purple and yellow colored traps were moderately effective in capturing bees, while the green color pan traps were least effective. Similarly, observed and extrapolated species richness was highest in blue trap, followed by purple, yellow, and green. Notably, the blue trap captured the highest number of unique species, followed by purple, yellow and green traps. Considering the total number of insects collected (including bees and other insects), yellow and green traps captured a significantly higher number of insects than other colored traps. The light reflectance from blue, purple, green and yellow pan traps had peaks at ~450, 400, 550, and 600 nm, respectively. Since different insects respond to different light intensities, wavelengths, and reflectivity, these results could be used to guide future trapping protocols targeting certain insect groups in livestock pasture and similar ecosystems.