Small-bodied males invest in larger testes when highly ornamented

Sperm competition and male mating rate are two non-mutually exclusive key evolutionary pressures selecting for larger testes within and across animal taxa. A few studies have tried to test the role of mating rate in the absence of sperm competition. Under the mating rate hypothesis, particular phenotypes of a given population that are expected to gain more mates (e.g., more ornamented males) are expected to make higher investments in testes size (a proxy for sperm production). We test this prediction in Polistes simillimus, a neotropical paper wasp in which females are single mated (no sperm competition) and males can mate with multiple partners. Testes size was predicted by body size (positive association), sexual ornamentation (negative association), and their interaction (among small males, testes size was positively related to ornamentation, but the opposite pattern was observed among large males). We propose that small-bodied well-ornamented males may face the highest risk of sperm depletion. Small-bodied males make relatively higher investment in testes size when highly ornamented. This strategy might be less profitable to large males, as they have overall larger testes. Our results provide strong evidence for the mating rate hypothesis.

Immune response in paper wasp workers: Task matters more than age

Workers of social hymenopterans (ants, bees and wasps) display specific tasks depending on whether they are younger or older. The relative importance of behavior and age in modulating immune function has seldom been addressed. We compared the strength of encapsulation-melanization immune response (hereafter melanotic encapsulation) in paper wasps displaying age polyethism or experimentally prevented from behavioral specialization. Foragers of Polybia paulista had higher melanotic encapsulation than guards, regardless of their age. Nevertheless, melanotic encapsulation decreased with age when wasps were prevented from behavioral specialization. Thus, in this species, worker melanotic encapsulation seems more sensitive to task than age. Foraging is considered one of the riskier behaviors in terms of pathogen exposure, so upregulating melanotic encapsulation in foragers can possibly improve both individual and colony-level resistance against infections.

A predatory social wasp does not avoid nestmates contaminated with a fungal biopesticide

Fungus-based biopesticides have been used worldwide for crop pest control as a safer alternative to chemical pesticides such as neonicotinoids. Both agrochemicals can be lethal and may also trigger side effects on the behavioral traits of non-target social insects, which play a crucial role in providing essential biological pest control services in agroecosystems. Here, we evaluated whether a commercial formulation of the entomopathogenic fungus Beauveria bassiana or the neonicotinoid imidacloprid causes mortality in foragers of Mischocyttarus metathoracicus. These social wasps are natural enemies of caterpillars and other herbivorous insects and inhabit both urban and agricultural environments in Brazil. We also tested whether wasps discriminate between biopesticide-exposed and unexposed conspecifics. Through a combination of laboratory (survival assay) and field experiments (lure presentation), along with chemical analyses (cuticular hydrocarbon profiles), we showed that topic exposure to the label rate of each pesticide causes a lethal effect, with the biopesticide exhibiting a slower effect. Moreover, wasps do not discriminate biopesticide-exposed from unexposed conspecifics, likely because of the similarity of their cuticular chemical profiles 24 h after exposure. Overall, the delayed lethal time at the individual level, combined with the indistinctive chemical cues of exposure and the lack of discrimination by conspecifics suggests that the fungal biopesticide may ultimately pose a threat to the colony survival of this predatory wasp.

Efficiency of essential oils in the control of the black bean aphid Aphis craccivora Koch (Hemiptera: Aphididae)

The black aphid Aphis craccivora Koch is one of the main pests of the caupi-bean crop Vigna unguiculata (L.) Walp. Due to the need to find effective and safe methods of control, there has been an increase in research seeking natural alternatives. Thus, the objective of this work was to evaluate the potential of essential oils from jatoba Hymenaea courbaril, copaiba Copaifera langsdorffii and aroeira Schinus terebinthifolius to control nymphs and adults of A. craccivora. The oils were extracted from the leaves by the hydrodistillation method, diluted to 0.1% in distilled water with 2% dimethyl sulfoxide (DMSO). Each treatment had four repetitions, plus a control with distilled water + 2% DMSO. The biotests were conducted in two stages: the first was conducted in the laboratory, under controlled conditions of temperature, relative humidity and photophase, and the second was conducted in the greenhouse, using only the treatment with the best laboratory test results. After 24, 48, 72, 96 and 120 hours of exposure, the insect mortalities were checked. In the first phase of the experiment, the aroeira oil showed 83.33% and 75.75% efficiency of mortality in nymphs and adults, respectively. In the greenhouse tests, this same oil showed 73.52% in nymphs and 62.85% in adults, opening new perspectives regarding its use as a natural insecticide for the control of the black aphid of the bean.

Morphological caste differences in primitively eusocial insects: the Van der Vecht organ of Mischocyttarus paper wasps

Nests of independent-founding primitively eusocial paper wasps are founded by one or a few females. Before worker emergence, foundresses must forage, sometimes leaving the nest unattended. Chemical defence - the application of ant repellent secretions of the Van der Vecht organ (VdVO) on the nest surface - allows brood protection when active defence is weak or not possible. After worker emergence, it is more likely that some wasps stay in the nest, so active nest defence may be more common. Given this constraint on the nest defence, selection for increasing the cuticular secretory area of the VdVO, to improve chemical defence, may be stronger in foundresses (queens) than in workers - morphological castes are hypothesized to evolve. We investigated the occurrence of morphological castes in the Neotropical paper wasp Mischocyttarus. Confirming our prediction, we found that in some (but not all) species, foundresses have a distinct increase in the secretory area of the VdVO in relation to workers; even though there is a strong overlap between caste phenotypes (incipient morphological castes). Implications of these findings for the evolution of morphological castes in primitively eusocial wasps are discussed.

Sexually dimorphic traits and male fertility in a paper wasp

Females of many social Hymenoptera commit their reproductive potential to a single male; they mate once and never re-mate. Sexual selection theory predicts that under this regimen female precopulatory mate choice is crucial. The targets of female choice, male secondary sexual traits, should convey information about the functional fertility of the male. Here, we evaluated semen quality and its correlates in the paper wasp Polistes dominula, a monandric species with a lek-based mating system. The main goal of the study was to test whether sperm viability and the total number of sperm covaried with sexually dimorphic abdominal spots, body size and parasitic infection by Xenos vesparum. Surprisingly, superior male fertility was not predicted by attractive sexual traits, such as little round spots and large body size. We also found no effect of the parasite on male fertility, sexual ornamentation or body size. We found only that sperm viability was positively associated with the number of sperm. Moreover, there was evidence of a counterintuitive relationship between (sexually unattractive) large irregular spots and large body size of dominant successful males. Overall, our results suggest a condition-dependent trade-off between body size and costly sexual signals.

Sexual ornaments reveal the strength of melanization immune response and longevity of male paper wasps

It has been recently suggested that female mate choice, based on sexually selected ornaments, is an important component of social wasps' reproductive biology. The correlates of male ornaments that could be of a female's interest, however, remain to be investigated. Males of the Neotropical paper wasp Polistes simillimus have sexually dimorphic melanin-based black spots on their faces. In this species, male spots work like sexual ornaments, as it has been experimentally demonstrated that females prefer sexual partners with a higher proportion of black pigment on their faces. We have shown that, under laboratory conditions, male sexual ornamentation positively predicts the strength of the melanization immune response and longevity. Therefore, in P. simillimus, melanin-based facial patterns (ornaments) seem to be honest indicators of male quality.

Ontogenic Caste Differences in the Van der Vecht Organ of Primitively Eusocial Neotropical Paper Wasps

Recent studies have reported incipient morphological caste dimorphism in the Van der Vecht organ size of some temperate Polistes paper wasps. Whether species other than the temperate ones show a similar pattern remains elusive. Here, we have studied some Neotropical Polistes species. By comparing females collected through the year, we showed caste related differences in the size of the Van der Vecht organ in P. ferreri (body size corrected Van der Vech organ size of queens = 0.45 ± 0.06, workers = 0.38 ± 0.07 mm², p = 0.0021), P. versicolor (body size corrected Van der Vech organ size of queens = 0.54 ± 0.11, workers = 0.46 ± 0.09 mm², p = 0.010), but not P. simillimus (body size corrected Van der Vech organ size of queens = 0.52 ± 0.05, workers = 0.49 ± 0.06 mm², p = 0.238). Therefore, it seems that queens and workers of some Neotropical Polistes have diverged in their ontogenic trajectory of the Van der Vecht organ size, providing clear evidence for incipient morphological caste dimorphism. As Polistes are distributed mostly in the tropics, we propose that physical caste differences may be widespread in the genus. Also, we highlight that morphological divergence in the queen–worker phenotypes may have started through differential selection of body structures, like the Van der Vecht organ.

DMAICR in an ergonomic risks analysis

The DMAICR problem-solving methodology is used throughout this paper to show you how to implement ergonomics recommendations. The DMAICR method consists of the following five six steps by which you can solve ergonomic design problems: The steps of the proposed method, adapting DMAICR, are the following: In the steep D, there is the definition of the project or the situation to be assessed and its guiding objectives, known as demand. In the step M, it relates to the work, tasks and organizational protocols and also includes the need of measuring. In the step A, all concepts are about the analysis itself. The step I is the moment of improving or incrementing. In the step C, control, prevention from prospective troublesome situation and implementation of management are the activities controlling the situation. R is Report. Some relevant technical and conceptual aspects for the comparison of these methodologies are illustrated in this paper. The steps of DMAICR were taken by a multifunctional team (multi-professional and multi-disciplinary) termed as focus group, composed by selected members of the company and supported by experts in ergonomics.

The relationship between the profile of severity of addiction and the retention of patients in the ambulatory program of DDTP

OBJECTIVES

The authors described some variables related to the retention of drug dependent veterans receiving outpatient treatment at San Juan V.A.M.C. and compared the profile of addiction severity with retention using a global dysfunction scale.

METHODS

The clinical charts of 74 patients were examined at random using a 16-item questionnaire based on the ASI scale. The data was processed and analyzed using the Epi Info V6.2 computer program, utilizing chi square as the main statistics.

RESULTS

The patient's retention in treatment for > or = to 3 months was associated with some specific variables such as: more than 12 years of education, being Catholic, divorced, living with parents, use of more than one drug of preference, having a negative urine toxicology result before treatment and after treatment, and showing a favorable change in urine toxicology results. In terms of severity of dysfunction, a considerable substance problem and an extreme legal problem were associated with a retention of > or = to 3 months, as well as no evidence of occupational problems.

CONCLUSION

The strong correlation between specific variables and the retention of patients in treatment for > or = to 3 months should create awareness of the importance of available and effective treatments in the fight against substance abuse and mental health problems as well as to educate and integrate family members in patients treatment, since a supportive family member is one of the best tools that patients and therapist can have to help maintain patient's sobriety.

A descriptive-exploratory study of outcome and some biopsychosocial characteristics of drug dependent veterans in Puerto Rico

OBJECTIVE

The authors attempted to correlate outcomes with various significant biopsychosocial variables in drug dependent veterans receiving outpatient treatment at San Juan V.A.M.C.

METHODS

The clinical charts of 120 inactive patients were examined using a 50 item questionnaire. The data was processed and analyzed using the EpiInfo v.5 computer program. The outcome of the patients was measured using a Goal Attainment Scale Technique with demonstrated validity and reliability.

RESULTS

The patients retention in treatment for 12 or more visits and its relationship to good outcomes was the most significant finding of this study (P < 0.00000000, 80.5% of patients improved). Only 5% of patients with 3 or less visits showed positive outcomes. Another variable associated with good outcomes was a supportive wife (P < 0.02). HIV reactivity was strongly correlated with IV drug use (P < 0.037).

CONCLUSIONS

The strong correlation of the retention of patients in treatment for 12 or more visits and good outcomes should alert clinicians and policy makers as to the importance of available and effective treatments in the fight against substance abuse and mental health problems. This study also showed that a supportive family member is usually the best social asset that patients and therapists have in their fight for sobriety.

A naturalistic analytic study of veterans using naltrexone in Puerto Rico

Clinical records of eighteen patients on Naltrexone and 13 patients who dropped out of a Naltrexone maintenance activity were studied at random to delineate the biopsychosocial characteristics of greater clinical relevance to an outpatient rehabilitation program. Their similarities and differences were described. Some hypothesis that may prove to be great clinical benefit were presented. A striking finding was the greater capacity of the Naltrexone group to have a stable marital relationship (P less than 0.01) as compared with the group who abandoned treatment.