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Insect behavior is coordinated mainly by smell through the diverse odor-binding proteins (OBP) that allow them to identify and recognize their environment. Sensory information collected through smell is then analyzed and interpreted in the brain, allowing for correct insect functioning. The behavior of honeybees (Apis mellifera L.) can be affected by different pathogens, such as deformed wing virus (DWV). In particular, the DWV variant A (DWV-A) is capable of altering olfactory sensitivity and reducing the gene expression of different OBPs, including those associated with nursing behavior. The DWV is also capable of replicating itself in the sensory lobes of the brain, further compromising the processing of sensory information. This study evaluated the behavioral response of nurse honeybees exposed to a pheromone compound and the alterations in the gene expression of the pre- and post-synaptic neuronal genes neuroxins-1 and neurogilin-1 in the bee heads and OBP proteins in the antennae of nurse bees inoculated with DWV-A. The behavioral response of nurse bees exposed to the larval pheromone compound benzyl alcohol was analyzed using a Y-tube olfactometer. The viral load, the gene expression of OBP5 and OBP11 in antennae, and neuroxins-1 and neurogilin-1 in the bee heads were analyzed via qPCR. High viral loads significantly reduced the ability of 10- and 15-day-old nurse honeybees to choose the correct pheromone compound. Also, the gene expression of OBP5, OBP11, neuroxin-1, and neurogilin-1 in nurse honeybees decreased when they were highly infected with DWV-A. These results suggest that a DWV-A infection can disturb information processing and cause nursing honeybees to reduce their activity inside the hive, altering internal cohesion.

Citriculture faces significant constraints in expanding into new environments and agroecological zones. Grafting onto tolerant rootstocks has helped overcome some of these limitations, enabling cultivation under diverse conditions. Nevertheless, citrus production remains vulnerable to multiple abiotic and biotic stressors, among which red mite ( Panonychus citri ) herbivory can markedly reduce yield and fruit quality. While rootstocks are known to influence scion physiology and defence capacity, their specific role in modulating responses to pest attack is still poorly understood. To address this, we evaluated 18-month-old ‘W. Murcott’ mandarin grafted onto four citrus rootstocks (‘Macrophylla’, ‘C35’, ‘Citrumelo’, ‘Carrizo citrange’) under semi-field conditions, infested or not with P. citri . After seven days of infestation (100–160 eggs/leaf), we quantified stress markers (malondialdehyde, proline, salicylic acid), physiological parameters, primary and secondary metabolites, volatile organic compounds (VOCs), and defence-related gene expression. Rootstocks significantly modulated constitutive and inducible responses. ‘Citrumelo’ and ‘Carrizo’ showed the lowest MDA accumulation and strongest induction of SA, PR5 , and GLR transcripts, coupled with increased emission of herbivory-induced plant volatiles (HIPVs, e.g., β-pinene, methyl salicylate, β-ocimene). ‘Macrophylla’ exhibited limited changes, whereas ‘C35’ displayed high MDA content and PITY1 induction, suggesting greater oxidative stress. Photosynthetic pigments declined across all combinations after infestation, while soluble sugars and flavonoids decreased in susceptible rootstocks. VOC profiles shifted both qualitatively and quantitatively in a rootstock-dependent manner. These results show that P. citri herbivory can amplify rootstock-driven differences in physiological, biochemical, and molecular traits, providing a basis for further studies on the role of rootstock–scion interactions in citrus resistance to mite attack.

We studied if testosterone and estradiol concentrations are associated with specific female waist-to-hip ratios (WHRs) and body mass indices (BMIs). Participants were 187 young women from which waist, hips, weight, and height were measured. In addition, participants informed on which day of their menstrual cycle they were and provided a 6 mL saliva sample. Ninety-one of them were in the follicular phase and 96 in the luteal phase. Only in the fertile phase of the menstrual cycle we found a significant interaction between testosterone and estradiol affecting WHR (b±s.e.=-0.000003±0.000001; t94=-2.12, adjusted R2=-0.008, P=0.03). Women with the highest levels of both hormones had the lowest WHRs, while women with low estradiol and high testosterone showed the highest WHRs. BMI significantly increased as testosterone increased in female in their nonfertile days.

The red mite, Oligonychus yothersi (McGregor) (Acari: Tetranychidae), is a serious pest of avocado (Persea americana Mill.) 'Hass' in Chile. Micro-coleopterans predators are observed in avocado orchards during outbreaks of O. yothersi, which are attracted by herbivore-induced plant volatiles (HIPVs). However, the damage to plants persists and new predators are needed. Due to its effectiveness and adaptability to dry climates, the western predatory mite Galendromus occidentalis (Nesbitt) (Acari: Phytoseiidae) has been adopted as a biological control agent on many crops. Ours objectives were to study the biological parameters of G. occidentalis preying on O. yothersi in controlled conditions and its attraction to volatile compounds from avocado shoots, live preys and four synthetic doses of methyl salicylate (MeSA) and ocimene using a Y-tube olfactometer. We found a net reproductive rate (Ro) 34.41 offspring female-1, intrinsic rate of increase (rm) 0.19 females female-1d-1, finite rate of increase (X) 1.21 females female-1, mean generation time (T) 18.45 d, and doubling time (DT) of 3.61 d. Immature phytoseiids took 7.32 d to reach adulthood with 90% survival. Female longevity and fecundity were 36.27 d, and 59 eggs female-1, respectively. Phytoseiids show no attraction to O. yothersi volatiles or volatiles of O. yothersi-infested avocado shoots. Nevertheless, females showed a preference for synthetic MeSA and ocimene at 100 µg mL-1. Our findings indicate that O. yothersi is a potential diet to rear G. occidentalis, and MeSA and ocimene could be used in lures to manipulate its behavior in avocado orchards.

Insects have a highly sensitive sense of smell, allowing them to perform complex behaviors, such as foraging and peer recognition. Their sense of smell is based on the recognition of ligands and is mainly coordinated by odorant-binding proteins (OBPs). In Apis mellifera, behavior can be affected by different pathogens, including deformed wing virus (DWV) and its variants. In particular, it has been shown that variant A of DWV (DWV-A) is capable of altering the ultra-cellular structure associated with olfactory activity. In this study was evaluated olfactory sensitivity and the expression of OBP genes in honey bees inoculated with DWV-A. Electroantennographic analyses (EAG) were carried out to determine the olfactory sensitivity to the essential oils Eucalyptus globulus and Mentha piperita. The expression of nine antenna-specific OBP genes and DWV-A load in inoculated bees was also quantified by qPCR. We observed an inverse relationship between viral load and olfactory sensitivity and the expression of some OBP proteins. Thus, high viral loads reduced olfactory sensitivity to essential oils and the gene expression of the OBP2, OBP5, OBP11, and OBP12 proteins on the antennas of middle- and forager-age bees. These results suggest that DWV-A could have negative effects on the processes of aroma perception by worker bees, affecting their performance in tasks carried out in and outside the colony.

The European grapevine moth (EGVM), Lobesia botrana (Denis & Schiffermuller), is a severe pest of grapes, since detected in Chile in 2008 has been subjected to an official control program by the Chilean Department of Agriculture, mainly in vineyards and orchards. Lobesia botrana has also been found in urban areas, mostly on backyard grapes, those have become important refuges for large L. botrana populations and significant sources for both dispersal and re-infestation to agricultural settings, thus the need for control. Chemical sprays are not allowed for intensive pest management in residential areas; therefore, the mating disruption technique has been the main tool to control L. botrana in cities. However, it is not always feasible to evenly deploy the required amount of dispenser ha1 in urban areas using conventional formulations. A new meso-dispenser (MeD), loaded with 10x the regular amount of pheromone of standard dispensers, and recommended at 50 units ha1, was evaluated in three consecutive seasons (2013-2016), in four cities in central Chile. This new dispenser yielded significantly lower male captures in traps in comparison with untreated areas. Cumulative male captures per individual fights per season, ranged between 292-2043 trap1 (MeD) and 15 795-28 403 trap1 (untreated), and significantly declined in the second and third seasons of MeD usage. Disruption index ranged between 68.9% and 98.9% considering fights individually, and above 88.0% considering whole seasons. The presence of eggs, larvae, and pupae infesting clusters, also significantly declined with the number of seasons treated with MeD.

Bull’s-eye rot, produced by Phlyctema vagabunda, is an important postharvest disease in apples. Current measures to control infection include synthetic fungicides, in addition to the application of copper hydroxide and potassium phosphite. However, growing public concern regarding fungicide residues in food has generated interest in developing non-chemical alternative control methods; biological control is one of the most promising alternatives. In this research, native endophytic yeasts were isolated and evaluated for the biocontrol of P. vagabunda in apples. The mechanisms of action involved were also determined. Our research found 2 isolates, Vishniacozyma victoriae EPL4.5 and EPL29.5, which exhibited biocontrol activity against P. vagabunda at 20 °C in apples, the incidence of bull’s-eye rot was reduced by 39% and 61%, respectively, and the severity of the disease was decreased by 67% and 70%, respectively, when apples were inoculated with these yeasts 24 h before applying the pathogen. The main mechanisms that could be involved in the observed biocontrol activity are the ability to form biofilms and the production of volatile organic compounds.

Some environmental variables determining seasonal reproduction in mammals are temperature, humidity, food availability, and photoperiod. Among these, photoperiod is considered the main regulator of primates’ seasonal reproduction, thus the latitudinal distribution of primate populations is a key factor determining the appearance of seasonal reproduction. The present work presents supporting discrete seasonality in male stump-tailed macaques ( Macaca arctoides ). We investigated whether semen quality and testosterone covaried with Mexico City’s photoperiod and relative humidity by analyzing variations in the portions that form the ejaculate: the seminal liquid, the seminal coagulum, and the copulatory plug. Five male adult stump-tailed macaques were electroejaculated once a month, obtaining three semen samples per male, from August 2011 to July 2012 (except for December 2011) ( n  = 165). Our results showed that stump-tailed macaque sperm counts were significantly different between the portions of the ejaculate. The seminal coagulum contained the significantly largest number of spermatozoids, followed by the copulatory plug and the seminal fluid. Photoperiod and relative humidity had major influence on the sperm count in the seminal coagulum and the testosterone concentrations. Testosterone reached its highest values around the time when days and nights lasted the same hours, decreasing when days either grew longer or became shorter. Concerning relative humidity, sperm counts in the seminal coagulum were highly variable on dry days, but decreased as the relative humidity increased. We conclude that stump-tailed macaques have a discrete seasonality, occurring in spring and fall when macaques’ reproductive condition and readiness for postcopulatory intrasexual competition increase.

The entomopathogenic nematode (EPN) Steinernema australe was isolated from Isla Santa Magdalena in Chile and identified as a good alternative for controlling Aegorhinus nodipennis (Coleoptera: Curculionidae) larvae. This weevil is native to the south of Chile and some regions in Argentina, causing the decline and ultimate death of plants in berry orchards. The major problem brought about by the weevil is caused by the larvae, which spend between nine and eleven months below ground, feeding inside the roots of the plants. This study seeks to increase S. australe’s efficacy through an artificial selection process using an odor stimulus. We selected infective juveniles (IJs) that followed the stimulus in order to reach larvae at a depth of 30 cm to achieve this objective. Larvae infected with selected IJs and IJs from the original stock were compared under laboratory, greenhouse, and field conditions. The results showed a 20% increase in the efficacy of selected IJs compared with IJs from the original stock. We observed a higher proportion of selected IJs that reached the larvae faster during the first four days post-application. Moreover, larvae treated with selected IJs were depleted, with a mix of nematode stages emerging from the cadaver. Finally, a potential trade-off with regard to the recycling of nematodes into the soil is proposed.

ABSTRACT Plants undergoing insect infestation release herbivore-induced plant volatiles (HIPVs) into their environment, which are then used by natural enemies for their benefit. The pest Aleurothrixus floccosus, which affects citrus orchards in northern Chile, specifically at Pica Oasis, poses a year-round threat. Recently, the introduction of the exotic ladybird Clitostethus arcuatus has been noted as a predator of A. floccosus. This study delved into how HIPVs emitted from tangelo (Citrus reticulata × C. ×paradisi Macfad.) and lime (C. ×aurantifolia (Christm.) Swingle) infested-shoots impact the behavioral responses of C. arcuatus. The volatile compounds were collected using the headspace technique, revealing notable qualitative changes after herbivory. In two-choice bioassays, the HIPVs elicited an attractive response in C. arcuatus compared to A. floccosus. At concentrations of 10 and 100 µg mL-1, the predators displayed a distinct preference for methyl salicylate (MeSA). These findings underscore that C. arcuatus exploits the HIPVs emitted from citrus infested-shoots, fostering tritrophic interactions. Exploring the impact of whitefly attacks on other fruit trees, emerges as a significant avenue for future investigation.