Search Results (6)

The cabbage whitefly has become an important pest on brassica vegetables in Central Europe. It does not destroy the affected plants, but the product becomes unmarketable, causing considerable economic losses. The pest is also difficult to control due to its way of life and because it develops resistance to some of the active components of insecticides. In organic farming systems, insecticides are strictly restricted, but neither predators nor whitefly parasitoids are able to keep the pest at a tolerable level. It is, therefore, necessary to become familiar with the whitefly’s life cycle and habits, including mass migration from winter hosts to vegetables. We inspected 44 rapeseed fields across the republic in the period 2014–2021 in order to find the connection between the presence of oilseed rape fields near vegetable growing areas (VGAs) and the abundance of the overwintering cabbage whiteflies. We also conducted regular weekly monitoring of whitefly occurrence in the main cultivation area of the Czech Republic (Polabí) with the aim of specifying critical data important for the successful control of this pest. We found that the cabbage whitefly incidences were many times higher in rapeseed fields close to VGAs compared to areas where the crops are not adjacent. The average number of whiteflies was 0.59 individuals per plant in VGA-1 (oilseed rape grown inside this area or up to 1 km far), 0.052 in VGA-2 (distance 3–10 km from vegetable fields) and 0.014 in VGA-3 (more than 20 km). In the extremely warm year 2016, the difference was up to sixty times. The first CW eggs laid on cruciferous vegetables were usually found around 20 May. The period of mass migration of CW adults to cruciferous vegetables was between 6 June and 2 August. At this time, vegetables are most vulnerable to damage. Successful control of the cabbage whitefly requires the use of fabric netting, combined with an insecticide as needed and trap plants as needed; the latter have to be destroyed before adult whiteflies hatch—typically in early July. Full article

The livestock sector is facing serious challenges in combatting the increasing predation of domestic livestock. In this scenario, wild carnivores, especially wolves, represent key predators. To allow the coexistence of wild and domestic animals, defense methodologies consisting of multiple integrated antipredator strategies must be tested and implemented based on the geographical management context of each farm. This study investigated the potential of a novel antipredator method (PAN, Project Farmers-Nature in Italian) in protecting livestock (goats and horses) from wolves on a farm located in the Sibillini Mountains National Park, over a three-month period (June–September 2022). The PAN field approach involved two phases: (1) interviews with farmers and inspections of how the farm and pasture are structured and (2) monitoring predator abundance using camera traps and transects in order to understand the wildlife habits. Information on predator movement around the grazing area was shared with the farmer, who was actively involved in implementing strategies to protect livestock. The stable presence of one pair of wolves was confirmed in the grazing area, placing grazing livestock at risk. The farmer was advised to strengthen the existing antipredator strategy (herd protection dogs) by introducing two trained Maremma-Abruzzese sheepdog puppies to protect his animals. The implemented actions demonstrate how professional experts can serve as a strategic intermediary between livestock and wildlife conservation in the management of the current conflicts. Full article

In this article, we study the existence and uniqueness of multiple positive periodic solutions for a Gilpin–Ayala predator-prey model under consideration by applying asymptotically periodic functions. The result of this paper is completely new. By using Comparison Theorem and some technical analysis, we showed that the classical nonlinear fractional model is bounded. The Banach contraction mapping principle was used to prove that the model has a unique positive asymptotical periodic solution. We provide an example and numerical simulation to inspect the correctness and availability of our essential outcomes. Full article

Even though behavioural and physiological reactions to predation risk exhibited by prey species have received considerable attention in scientific journals, there are still many questions still unsolved. Our aim was to broaden the knowledge on one specific question: do long-tailed pygmy rice rats adapt their behavioural and physiological antipredator strategies depending on the predator species? For this question, we live-trapped in a temperate forest in Southern Chile long-tailed pygmy rice rats (Oligoryzomys longicaudatus), which were exposed to three predator odour phases (Phase 0: preliminary, no predator cues; Phase 1: one plot with culpeo fox faeces (Lycalopex culpaeus), one plot with lesser grison (Galictis cuja) faeces and one plot acting as a control with no odour; Phase 2: post treatment, no predator cues). We measured the behavioural response by the capture ratio. To assess the physiological stress response, we collected fresh faecal samples to quantify faecal corticosterone metabolites (FCM). Our results showed that O. longicaudatus increased both the capture ratio and FCM levels in the presence of culpeo cues. Culpeo foxes have higher densities in the study area than G. cuja and exhibit a higher activity pattern overlap with O. longicaudatus. Moreover, it has been also been reported in other regions that L. culpaeus consumption of O. longicaudatus is more frequent compared to G. cuja diet. The increase in capturability could be because traps can be regarded as a shelter in high-risk settings, but it can also be explained by the predator inspection behaviour. The increase in FCM concentrations during culpeo treatment can be linked to the adaptive mobilisation of energy to execute antipredator responses to increase survival chances. Full article

The “citrus greening disease” or huanglongbing is caused by the Gram-negative bacterium Candidatus liberibacter spp. One vector of HLB, the African citrus psyllid Trioza erytreae (del Guercio, 1918), was recorded for the first time in 2014 in mainland Spain and since then it has spread throughout the Iberian Peninsula. Measures against T. erytreae include chemical treatments and quarantine although eradication programmes have been of limited success or even failed. The biological control of T. erytreae has been little developed yet. Among natural enemies, spiders may encompass a promising group of predators. The objective of this work was to assess the potential of spiders as natural enemies of T. erytreae. A Citrus limon orchard was selected in northwestern Portugal in the area colonized by T. erytreae. A total of 100 webs (50 above and 50 below 1.5 m) were visually inspected throughout the orchard in August 2020. The family of the web-builder, web size, number of adults of T. erytreae captured by each web, and the temperature and humidity were registered. Temperature and humidity did not significantly differ between the two vertical strata. Web size was significantly higher in the lower strata whereas the number of captured adults of T. erytreae was significantly higher in the upper strata. The dominant family in the upper strata was Theridiidae corresponding with the most successful webs capturing adults of T. erytreae. Our results suggest that web architecture was the only factor driving the number of captured adults of T. erytreae. Thus, space web builders could be the most successful natural enemies of T. erytreae among aerial web builders. Full article

Lateralisation of eye use indicates differential specialisation of the brain hemispheres. We tested eye use by zebra finches to view a model predator, a monitor lizard, and compared this to eye use to view a non-threatening visual stimulus, a jar. We used a modified method of scoring eye preference of zebra finches, since they often alternate fixation of a stimulus with the lateral, monocular visual field of one eye and then the other, known as biocular alternating fixation. We found a significant and consistent preference to view the lizard using the left lateral visual field, and no significant eye preference to view the jar. This finding is consistent with specialisation of the left eye system, and right hemisphere, to attend and respond to predators, as found in two other avian species and also in non-avian vertebrates. Our results were considered together with hemispheric differences in the zebra finch for processing, producing, and learning song, and with evidence of right-eye preference in visual searching and courtship behaviour. We conclude that the zebra finch brain has the same general pattern of asymmetry for visual processing as found in other vertebrates and suggest that, contrary to earlier indications from research on lateralisation of song, this may also be the case for auditory processing. Full article