Increase In Progeny Research Articles

Tomato spotted wilt orthotospovirus influences the reproduction of its insect vector, western flower thrips, Frankliniella occidentalis, to facilitate transmission.

Tomato spotted wilt orthotospovirus (TSWV), one of the most devastating viruses of ornamental plants and vegetable crops worldwide, is transmitted by the western flower thrips, Frankliniella occidentalis (Pergande), in a persistent-propagative manner. How TSWV influences the reproduction of its vector to enhance transmission and whether infection with TSWV changes the mating behavior of F. occidentalis are not fully understood. TSWV-exposed thrips had a significantly longer developmental time than non-exposed individuals. More importantly, increased developmental time was predominantly associated with adults, a stage critical for dispersal and virus transmission. In addition, TSWV-exposed F. occidentalis produced substantially more progeny than did non-exposed thrips. Interestingly, most of the increase in progeny came from an increase in males, a sex with a greater dispersal and virus transmission capability. Specifically, the female/male ratio of progeny shifted from 1.3-7.0/1 to 0.6-1.1/1. As for mating behavior, copulation time was significantly longer in TSWV-exposed thrips. Finally, females tended to re-mate less when exposed to the virus. Resistance to re-mating may lead to reduced sperm availability in females, which translates to a larger number of male progeny under a haplodiploid system. These combined results suggest that TSWV can influence the developmental time, mating behavior, fecundity, and offspring sex allocation of its vector F. occidentalis to facilitate virus transmission. As such, a monitoring program capable of the earlier detection of the virus in host plants and/or its insect vector, thrips, using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), real time quantitative polymerase chain reaction (RT-qPCR) or virus detection strips might be beneficial for long-term, sustainable management. © 2020 Society of Chemical Industry.

Germination in Three Switchgrass Populations after Two Cycles of Divergent Selection for Seed Weight

Switchgrass (Panicum virgatum L.) is an emerging bioenergy crop in the US, but little has been done by breeders to improve its poor seed germination and slow and inconsistent establishment. The objective of this study was to evaluate the effects of divergent selection for seed weight on germination in three switchgrass populations over two cycles with and without a cold stratification treatment. Seed from switchgrass populations 9064202, ‘Carthage’, and ‘Timber’ was sorted into light and heavy weight classes via a gravity deck and germinated in a growth chamber. Seedlings were planted to the field in isolated crossing blocks. Seed from these blocks was sorted and germinated following a divergent selection scheme for a second cycle. Seed was harvested from all derived crossing blocks representing all cycles of selection and subjected to a cold or no stratification treatment and germinated in a growth chamber. One cycle of selection for heavy seed resulted in an increase in progeny seed weight in 9064202 and Carthage but not Timber. A second cycle of selection gave unexpected results, probably due to the effects of genetic drift. The effect of seed weight was not significant for germination percentage or germination rate index. Dormancy had a larger impact on overall germination and germination rate than seed weight in the populations tested. Therefore, selection efforts focused on reducing dormancy rather than increasing seed weight are likely to be more successful in improving overall germination and germination rate in switchgrass population 9064202 and cultivars Carthage and Timber.

Prepregnancy obesity and sFlt1-induced preeclampsia in mice: developmental programming model of metabolic syndrome

We sought to establish a model of fetal programming of metabolic syndrome by exposure to soluble fms-like tyrosine kinase-1 (sFlt1)-induced preeclampsia (PE) and preexisting maternal obesity (MO). CD-1 female mice were placed on either standard or high-fat diet for 3 months. On day 8 of pregnancy, mice were injected with either adenovirus-carrying sFlt1 or adenovirus-carrying murine immunoglobulin G2α Fc fragment. Offspring were studied at 6 months of age. Exposure to MO with/without PE resulted in significant increase in progeny's weight and adiposity. Blood pressure in males was significantly increased due to MO with PE. Metabolic blood analytes were affected in males and females exposed to only PE or MO with/without PE; inflammatory-in females exposed to MO with/without PE and males born to MO with PE; atherosclerotic-in females exposed to MO. Exposure to maternal prepregnancy obesity and sFlt1-induced preeclampsia alter the offspring's blood pressure, metabolic, inflammatory, and atherosclerotic profiles later in life.

Increasing Coffee Berry Borer (Coleoptera: Curculionidae: Scolytinae) Female Density in Artificial Diet Decreases Fecundity

Three experiments were conducted to determine the influence of number of coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), females (one, two, or five) reared in artificial diet on fecundity and subsequent development of larvae, pupae, and adults. Our results demonstrated that increasing female density from one to two or five individuals did not result in the expected two- or five-fold increase in progeny, despite ample food resources available. Instead, decreased fecundity was observed with increasing density for all experiments. The mechanism reducing fecundity was not identified, but possibly, volatiles are being produced (e.g., host-marking pheromones). The decrease in fecundity may explain why infestations of only one colonizing female per berry are the norm in the field.

Using rainfall radar data to improve interpolated maps of dose rate in the Netherlands

The radiation monitoring network in the Netherlands is designed to detect and track increased radiation levels, dose rate more specifically, in 10-minute intervals. The network consists of 153 monitoring stations. Washout of radon progeny by rainfall is the most important cause of natural variations in dose rate. The increase in dose rate at a given time is a function of the amount of progeny decaying, which in turn is a balance between deposition of progeny by rainfall and radioactive decay. The increase in progeny is closely related to average rainfall intensity over the last 2.5 h. We included decay of progeny by using weighted averaged rainfall intensity, where the weight decreases back in time. The decrease in weight is related to the half-life of radon progeny. In this paper we show for a rainstorm on the 20th of July 2007 that weighted averaged rainfall intensity estimated from rainfall radar images, collected every 5 min, performs much better as a predictor of increases in dose rate than using the non-averaged rainfall intensity. In addition, we show through cross-validation that including weighted averaged rainfall intensity in an interpolated map using universal kriging (UK) does not necessarily lead to a more accurate map. This might be attributed to the high density of monitoring stations in comparison to the spatial extent of a typical rain event. Reducing the network density improved the accuracy of the map when universal kriging was used instead of ordinary kriging (no trend). Consequently, in a less dense network the positive influence of including a trend is likely to increase. Furthermore, we suspect that UK better reproduces the sharp boundaries present in rainfall maps, but that the lack of short-distance monitoring station pairs prevents cross-validation from revealing this effect.

Manipulation of food resources by a gall-forming aphid: the physiology of sink-source interactions

We examined the capacity of the galling aphid, Pemphigus betae, to manipulate the sink-source translocation patterns of its host, narrowleaf cottonwood (Populus angustifolia). A series of 14C-labeling experiments and a biomass allocation experiment showed that P. betae galls functioned as physiologic sinks, drawing in resources from surrounding plant sources. Early gall development was dependent on aphid sinks increasing allocation from storage reserves of the stem, and later development of the progeny within the gall was dependent on resources from the galled leaf blade and from neighboring leaves. Regardless of gall position within a leaf, aphids intercepted 14C exported from the galled leaf (a non-mobilized source). However, only aphid galls at the most basal site of the leaf were strong sinks for 14C fixed in neighboring leaves (a mobilized source). Drawing resources from neighboring leaves represents active herbivore manipulation of normal host transport patterns. Neighboring leaves supplied 29% of the 14C accumulating in aphids in basal galls, while only supplying 7% to aphids in distal galls. This additional resource available to aphids in basal galls can account for the 65% increase in progeny produced in basal galls compared to galls located more distally on the leaf and limited to the galled leaf as a food resource. Developing furits also act as skins and compete with aphid-induced sinks for food supply. Aphid success in producing galls was increased 31% when surrounding female catkins were removed.

EFFECTS OF HUMIDITY AND PHOSPHORUS ON POPULATIONS OF THE EUROPEAN RED MITE PANONYCHUS ULMI (ACARI: TETRANYCHIDAE)1

A laboratory study investigating the combined effects of phosphorus and relative humidity upon reproduction by the European red mite Panonychus ulmi (Koch) was conducted. Phosphorus effects were tested at two levels (Hoagland solution with or without phosphorus) and relative humidity at five levels (6%, 30%, 60%, 75% and 90%). Experiments were run at two temperatures, 21°C and 25°C, and at a day-length regime of 16L:8D. The mites' response to phosphorus was characterized by a significant increase in progeny numbers when the host plant contained “high” levels of this element. Reaction to humidity was characterized by an increase in progeny at relative humidities between 60% and 75%. Under the same RH conditions, higher numbers of progeny were generally obtained from plants containing higher levels of phosphorus; the most favorable treatment was Hoagland solution with phosphorus and 75% RH.