Coffee Fruit Rot: The Previously Unrecognized Role of Fusarium and Its Interactions with the Coffee Berry Borer (Hypothenemus hampei).

Coffee fruit rot (CFR) is a well-known disease worldwide, mainly caused by Colletotrichum spp., the most important species being C. kahawae subsp. kahawae. In Puerto Rico, Colletotrichum spp. were identified as pathogens of coffee fruits. The coffee berry borer (CBB) was shown to be a dispersal agent of these fungi, and interaction of Fusarium with Colletotrichum affecting coffee fruits was suggested. In this study, we demonstrated that Fusarium spp. also cause CFR in Puerto Rico. Fusarium spp. are part of the CBB mycobiota, and this insect is responsible for spreading the pathogens in coffee fields. We identified nine Fusarium spp. (F. nirenbergiae, F. bostrycoides, F. crassum, F. hengyangense, F. solani-melongenae, F. pseudocircinatum, F. meridionale, F. concolor, and F. lateritium) belonging to six Fusarium species complexes isolated from CBBs and from rotten coffee fruits. Pathogenicity tests showed that F. bostrycoides, F. lateritium, F. nirenbergiae, F. solani-melongenae, and F. pseudocircinatum were pathogens causing CFR on green coffee fruits. F. bostrycoides was the predominant species isolated from the CBB mycobiota and coffee fruits with symptoms of CFR, suggesting a close relationship between F. bostrycoides and the CBB. To our knowledge, this is the first report of F. bostrycoides, F. solani-melongenae, F. pseudocircinatum, and F. nirenbergiae causing CFR worldwide and the first report of F. lateritium causing CFR in Puerto Rico. Understanding the CFR disease complex and how the CBB contributes to dispersing different Fusarium spp. on coffee farms is important to implement disease management practices in Puerto Rico and in other coffee-producing countries.

An aggressive nonconsumptive effect mediates pest control and multipredator interactions in a coffee agroecosystem.

Natural pest control is an alternative to pesticide use in agriculture, and may help to curb insect declines and promote crop production. Nonconsumptive interactions in natural pest control that historically have received far less attention than consumptive interactions, may have distinct impacts on pest damage suppression and may also mediate positive multipredator interactions. Additionally, when nonconsumptive effects are driven by natural enemy aggression, variation in alternative resources for enemies may impact the strength of pest control. Here we study control of the coffee berry borer (CBB), Hypothenemus hampei, by a keystone arboreal ant species, Azteca sericeasur, which exhibits a nonconsumptive effect on CBB by throwing them off coffee plants. We conducted two experiments to investigate: (1) if the strength of this behavior is driven by spatial or temporal variability in scale insect density (an alternative resource that Azteca tends for honeydew), (2) if this behavior mediates positive interactions between Azteca and other ground-foraging ants, and (3) the effect this behavior has on the overall suppression of CBB damage in multipredator scenarios. Our behavioral experiment showed that nearly all interactions between Azteca and CBB are nonconsumptive and that this behavior occurs more frequently in the dry season and with higher densities of scale insects on coffee branches. Our multipredator experiment revealed that borers thrown off coffee plants by Azteca can survive and potentially damage other nearby plants but may be suppressed by ground-foraging ants. Although we found no non-additive effects between Azteca and ground-foraging ants on overall CBB damage, together, both species resulted in the lowest level of plant damage with the subsequent reduction in "spillover" damage caused by thrown CBB, indicating spatial complementarity between predators. These results present a unique case of natural pest control, in which damage suppression is driven almost exclusively by nonconsumptive natural enemy aggression, as opposed to consumption or prey behavioral changes. Furthermore, our results demonstrate the variability that may occur in nonconsumptive pest control interactions when natural enemy aggressive behavior is impacted by alternative resources, and also show how these nonconsumptive effects can mediate positive interactions between natural enemies to enhance overall crop damage reduction.

Coffee pest severity by agrometeorological models in subtropical climate.

This study aimed to estimate the number of generations and cycle duration of the southern red mite, coffee berry borer, and coffee leaf miner using the thermal index to assist in controlling these main coffee pests in the state of Paraná, Brazil. The data of maximum and minimum air temperature (°C) and precipitation (mm) of all municipalities in the state from 1984 to 2018 were collected from the National Aeronautics and Space Administration/Prediction of Worldwide Energy Resources (NASA/POWER). The reference evapotranspiration was estimated using the (Camargo Campinas IAC Boletim 116:9, 1971) method and the water balance was calculated using the method of ( Thornthwaite C, Mather J (1955) The water balance publications in climatology, 8 (1). DIT, Laboratory of climatology, Centerton, NJ, USA). The basal temperature of each pest minus the average temperature of the years was used to calculate the degrees-day, the duration of the pest cycle, and the number of generations per year. The influence of altitude on the development of coffee pests was measured using the Pearson correlation. The thermal index is able to estimate the damage caused by coffee pests in the state of Pará, Brazil. Coffee pests show greater severity in the north of Paraná, in the regions with the highest temperatures. It is the same region that concentrates most of the coffee production of the state. The results of the life cycle and number of generations were interpolated for the entire state using the kriging method. Coffee pests showed the highest severity in the north region of the state of Paraná, more specifically in the Northwest, North Central, and West Central mesoregions. These regions have concentrated most of the state's coffee production. Mesoregions with the highest coffee production in the state showed higher susceptibility to coffee pests. Altitude showed a high correlation (r > 0.6) with the cycle variability and number of generations of coffee pests. The average cycles of the coffee berry borer, coffee leaf miner, and southern red mite are 24.13 (± 8.34), 45.64 (± 18.61), and 21.51 (± 3.51) days, respectively. The average annual generation was 16.67 (± 4.77), 9.02 (± 2.75), and 17.32 (± 2.63) generations, for the coffee berry borer, the coffee red mite, and the southern red mite, respectively.

Emergence and Infestation Level of Hypothenemus hampei (Coleoptera: Curculionidae) on Coffee Berries on the Plant or on the Ground During the Post-harvest Period in Brazil.

The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae), is the most important coffee pest in most of the coffee growing countries. CBB females leave old dry berries after harvest and search for dry noninfested berries on the plant or on the ground to lay eggs or to use as refuge until new berries are available on the coffee trees in the following season. The CBB infestation level and emergence from berries on the ground or on the plants were evaluated in two fields post-harvest in the Spring in Brazil over two seasons. Twenty infested or noninfested berries in separate cages (250 ml plastic cups) were placed on the plants or on the ground under the tree canopy, in each field. The number of infested berries and CBB females that emerged from the infested berries were recorded weekly. CBB emergence was higher from berries on the ground than those on the coffee trees in both seasons, whereas CBB infestation was higher on coffee berries on the plants than those on the ground in season I. Insolation (hours of sunlight) and temperature were the main covariates that affected emergence and infestation by this insect. The results are discussed for monitoring CBB during the time of dispersal with implications on integrated management of this pest.

Evaluation of Terpene-Volatile Compounds Repellent to the Coffee Berry Borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae).

The coffee berry borer (CBB) is one of the main coffee pests in the world including Colombia. This pest is difficult to manage because of its cryptic habits and the continuous availability of coffee fruits. Among the new management strategies being tested is the use of volatile compounds as insect repellents. In this work, the behavioral response of female adult CBBs to terpenes previously identified in the CBB-repellent plant species Lantana camara was evaluated. α-Terpinene, (R)-limonene, farnesene and ß-caryophyllene terpenes were tested via a Y-tube olfactometer in which ripe coffee fruits were accompanied by terpenes at concentrations between 25 and 200 ppm. Only ß-caryophyllene induced a significant and consistent CBB repellent effect at all tested doses. The protective effect of microencapsulated ß-caryophyllene was then determined under laboratory conditions by incorporating the terpene in a colloidosome-gel system at 2.8 × 105 ng/h in the middle of coffee fruits with adult CBBs. The coffee fruits in turn presented a decrease in fruit infestation. Furthermore, the protection of coffee fruits when ß-caryophyllene gels were hung in coffee trees was evaluated in the field; infestations were artificially induced by the use of raisins (CBB-infested old coffee fruits) placed on the ground. Compared with unprotected trees, the trees treated with caryophyllene gels exhibited a 33 to 45% lower degree of infestation. Taken together, the results show that ß-caryophyllene is a promising compound for an integrated pest management (IPM) program in commercial coffee plantations.

The singular insemination status of Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) females during the inter-harvest season of a coffee crop.

The coffee berry borer, Hypothenemus hampei (Ferrari), can survive in residual coffee berries during the inter-harvest period, while new fructification only appears 2-3 months after the last harvest. The dispersal of colonizing females is an adaptation that enables the life cycle of the species to go ahead whenever his flight aptitude allows. This paper focuses on accurately determining the rate of inseminated females ready to reproduce when emerging from residuals berries to colonize new ones, which constitutes a characteristic of the live cycle far from common in Curculionidae. We dissected females caught in traps baited with a mixture of alcohols during the inter-harvest season, females from infested residual berries collected from branches, and virgin females obtained from pupae reared individually in the laboratory. After microscopic preparation with Giemsa stain, spermathecae were observed to identify the physiological status of each specimen. Out of the females found in the traps, 98.4% displayed recent and abundant insemination and 1.6% sporadic insemination. In contrast, in residual berries, most of females were recently inseminated (84.5%), followed by virgin females (10.5%) and older inseminated females (5%). In addition, the flight tests of the virgin females were negative. These results indicate that all colonizing females were inseminated, ready for flying and oviposition, females inside residual berries showed different physiological status, and virgin females could not migrate since they could not flight. The large number of inseminated females inside the residual berries, and the capacity of migrating females to colonize and reproduce, suggest that it is necessary to control residual berries and use traps to stop the dispersal and reproduction of this pest.

High diversity and variability in the bacterial microbiota of the coffee berry borer (Coleoptera: Curculionidae), with emphasis on Wolbachia.

AIMS: Variation in microbiota of the coffee berry borer (CBB) Hypothenemus hampei was studied. Diversity, structure and function of bacterial communities were compared between eggs vs adults, CBBs from shade coffee vs sun coffee, CBBs from the field vs raised in the laboratory, and CBBs with and without the antibiotic tetracycline. METHODS AND RESULTS: We sequenced the region V4 of the gene 16 S rRNA. Pseudomonadaceae and Enterobacteriaceae, particularly Pseudomonas and Pantoea, dominated microbiotas of the CBB. Comparative functional inferences with PICRUSt suggested that samples from the field were enriched for genes involved in carbohydrate and protein digestion and absorption, while laboratory-reared samples were higher in genes for melanization and caffeine metabolism. CONCLUSIONS: Microbiotas of the CBB were diverse and dominated by the genus Pseudomonas, several species of which have been previously associated with caffeine degradation in this insect. Wolbachia was the only endosymbiont detected with known ability to manipulate host reproduction. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that stage of development and origin of samples affected the structure and function of the CBB's bacterial communities. This is the first attempt to predict functional significance of the CBB microbiota in nutrition, reproduction and defence.

Collection, isolation, in vitro culture, and laboratory transmission of Hirsutella eleutheratorum (Hypocreales: Ophiocordycipitaceae) from coffee berry borer on Hawai'i Island.

The insect pathogenic fungus Hirsutella eleutheratorum was first reported as a pathogen of coffee berry borer (CBB) Hypothenemus hampei in Colombia in 1993. A similar CBB pathogen identified as Hirsutella sp. was reported also from Colombia in 2007; attempts at isolation and in vitro culture of this fungus were unsuccessful. During 2016 and 2017 on the island of Hawai'i, extensive sampling of CBB populations was conducted in coffee fields treated with Beauveria bassiana-based biopesticides and in untreated fields. Among the samples collected from two high-elevation sites in the district of South Kona were rare findings of adult foundress CBB infected with a species of Hirsutella fitting the description of H. eleutheratorum. Prevalence of the pathogen was, in all cases, very low (<1%), having no significant impact on pest populations, even under conditions supporting epizootics of B. bassiana. The fungus was readily isolated from freshly-killed CBB and cultured on potato dextrose agar (PDA). Molecular characterization identified the fungus as a member of the Hirsutella citriformis clade, which includes species recently placed in the genus Ophiocordyceps. Adult CBB exposed to fungus-killed beetles or to PDA cultures of the fungus succumbed to infection within 10-14 days. Under high-humidity laboratory conditions, the fungus emerged from the killed host and produced long, conidia-bearing synnemata characteristic of the species. To our knowledge, this is the first record of H. eleutheratorum from CBB in Hawai'i and the first account of isolation, in vitro culture, genetic characterization, host-to-host transfer, and culture-to-host transfer of this fungal pathogen.

Prevalence of naturally-occurring strains of Beauveria bassiana in populations of coffee berry borer Hypothenemus hampei on Hawai'i Island, with observations on coffee plant-H. hampei-B. bassiana interactions.

Beauveria bassiana (Bb) strain GHA is a major component of an areawide pest management program for coffee berry borer (CBB) in Hawai'i. Recent studies have aimed to provide comprehensive assessments of the efficacy of the Bb-spray component of these programs for economic analyses; however, evaluations have been complicated by activity of naturally-occurring strains of this pathogen infecting CBB. Investigations were therefore undertaken to characterize these strains, assess their natural epizootic potential, and account for their contribution to CBB population suppression. A number of field sites were encountered with no history of significant use of commercial Bb-based biopesticides and where strain GHA was not detectable. Sampling of these sites was conducted early in the coffee season. Greatest activity of wild-type Bb strains was observed on high-elevation farms (>500 m), where 24-42% of foundress beetles in green coffee berries were infected. In contrast, infection rates did not exceed 4% on farms at low elevations (<300 m). Rates of 23-29% infection, comparable to those on high-elevation farms, were recorded in a stand of feral coffee at 293 m elevation, but the coffee was completely shaded and ventilation restricted by a dense overstory of vegetation. Despite high activity of naturally-occurring Bb at some sites (primarily sites at high elevations with humid, moderate-temperature environments and dense pest populations), these fungi did not prevent CBB from exceeding the economic threshold for commercial spray applications. Nevertheless, the high natural epizootic potential of these fungal strains suggests strong potential for development as microbial biocontrol agents.

Short-distance dispersal of Hypothenemus hampei (Ferrari) females (Coleoptera: Curculionidae: Scolytidae) during the coffee tree fruiting period.

The coffee berry borer (CBB), Hypothenemus hampei (Ferrari), is a multivoltine species closely associated with coffee crops worldwide, causing severe damage to the bean. In Mexico, as in all tropical regions, CBB survives during the inter-harvest period in residual berries on the ground or in dry berries remaining on the branches, and then disperses in search of the first suitable berries. In this study, we investigated how CBB dispersed from the first infested nodes during the fruiting period of Coffea canephora Pierre, which provides a favourable trophic level for this insect. Forty-five branches equally distributed in 15 coffee trees, with one infested node and four uninfested nodes, were selected. The branches were subjected to three treatments over nine weeks: 1) glue between nodes with full protection, 2) glue between nodes without protection, and 3) no glue and no protection. In addition, 45 CBB-free branches were selected and subjected to the same three treatments. CBB colonization can occur in three ways: 1) from an infested node to an uninfested node on the same branch, 2) from infested berries to uninfested berries within the nodes, 3) from branches to other branches. We also found that CBB dispersal between nodes of the same branches never occurred by walking but by flying. Thus, in this context of coffee berry development and ripening, and unlike the phenological situation of the inter-harvest period, CBB continuously travels very short distances, thus limiting its control.

Genome-wide analysis of transposable elements in the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae): description of novel families.

The coffee berry borer (CBB) Hypothenemus hampei is the most limiting pest of coffee production worldwide. The CBB genome has been recently sequenced; however, information regarding the presence and characteristics of transposable elements (TEs) was not provided. Using systematic searching strategies based on both de novo and homology-based approaches, we present a library of TEs from the draft genome of CBB sequenced by the Colombian Coffee Growers Federation. The library consists of 880 sequences classified as 66% Class I (LTRs: 46%, non-LTRs: 20%) and 34% Class II (DNA transposons: 8%, Helitrons: 16% and MITEs: 10%) elements, including families of the three main LTR (Gypsy, Bel-Pao and Copia) and non-LTR (CR1, Daphne, I/Nimb, Jockey, Kiri, R1, R2 and R4) clades and DNA superfamilies (Tc1-mariner, hAT, Merlin, P, PIF-Harbinger, PiggyBac and Helitron). We propose the existence of novel families: Hypo, belonging to the LTR Gypsy superfamily; Hamp, belonging to non-LTRs; and rosa, belonging to Class II or DNA transposons. Although the rosa clade has been previously described, it was considered to be a basal subfamily of the mariner family. Based on our phylogenetic analysis, including Tc1, mariner, pogo, rosa and Lsra elements from other insects, we propose that rosa and Lsra elements are subfamilies of an independent family of Class II elements termed rosa. The annotations obtained indicate that a low percentage of the assembled CBB genome (approximately 8.2%) consists of TEs. Although these TEs display high diversity, most sequences are degenerate, with few full-length copies of LTR and DNA transposons and several complete and putatively active copies of non-LTR elements. MITEs constitute approximately 50% of the total TEs content, with a high proportion associated with DNA transposons in the Tc1-mariner superfamily.

Molecular Markers Detect Cryptic Predation on Coffee Berry Borer (Coleoptera: Curculionidae) by Silvanid and Laemophloeid Flat Bark Beetles (Coleoptera: Silvanidae, Laemophloeidae) in Coffee Beans.

The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), is a serious pest of coffee worldwide. It was first detected in Hawai'i in 2010. Two predatory beetles, Cathartus quadricollis (Coleoptera: Silvanidae) and Leptophloeus sp. (Coleoptera: Laemophloeidae), have been observed in H. hampei-infested coffee. Under laboratory conditions, colony-reared C. quadricollis and Leptophloeus sp. prey upon all life stages of H. hampei. However, the H. hampei life cycle occurs almost exclusively within a coffee bean obscured from direct observation. Thus, it is unknown if C. quadricollis and Leptophloeus sp. consume H. hampei as prey in the wild. To demonstrate predation of H. hampei by C. quadricollis and Leptophloeus sp., a molecular assay was developed utilizing species-specific primers targeting short regions of the mitochondrial COI gene to determine species presence. Using these primers, wild C. quadricollis and Leptophloeus sp. were collected and screened for the presence of H. hampei DNA using PCR. Analysis of collections from five coffee farms revealed predation of C. quadricollis and Leptophloeus sp. on H. hampei. Further laboratory testing showed that H. hampei DNA could be detected in predators for as long as 48 h after feeding, indicating the farm-caught predators had preyed on H. hampei within 2 d of sampling. This study demonstrates the utility of molecular markers for the study of the ecology of predators and prey with cryptic behavior, and suggests C. quadricollis and Leptophloeus sp. might be useful biocontrol agents against H. hampei.

Neem-Extract Formulation on Hypothenemus hampei Preference and Performance in Arabica Coffee Fruits and Artificial Diet.

Coffee berry borer (CBB) Hypothenemus hampei is a major biotic threat to coffee production worldwide. Studies have reported negative effects on CBB by oil-based formulations of neem (Azadirachta indica), but little information is available for other neem-extract formulations. This study evaluated CBB preference and performance in arabica coffee fruits and artificial diet treated with a neem-extract formulation (Openeem Plus®) in the field and laboratory conditions. Field experiments were performed using CBB females artificially infested in cherry or green coffee fruits confined in voile-fabric cages tied to branches of neem-treated and control plants, recording the adult mortality and offspring production. Dual-choice and no-choice bioassays assessed CBB preference and development in fruits and artificial diet treated with the neem extract compared to controls in the laboratory, respectively. As main results obtained in the field and laboratory experiments, the neem extract significantly reduced CBB oviposition in both cherry and green fruits, as well as in artificial diet compared to controls. However, the botanical product did not affect CBB adult survival and preference in the laboratory bioassays. The neem extract is promising for use in pest management strategies in sustainable arabica coffee crops by reducing CBB oviposition and offspring. These effects can contribute to lowering the pest population buildup along the crop cycle and damage potential to coffee production.

Cordyceps cateniannulata: An endophyte of coffee, a parasite of coffee leaf rust and a pathogen of coffee pests.

Here, we report on a Cordyceps species entering into a multi-trophic, multi-kingdom association. Cordyceps cateniannulata, isolated from the stem of wild Coffea arabica in Ethiopia, is shown to function as an endophyte, a mycoparasite and an entomopathogen. A detailed polyphasic taxonomic study, including a multilocus phylogenetic analysis, confirmed its identity. An emended description of C. cateniannulata is provided herein. Previously, this species was known as a pathogen of various insect hosts in both the Old and New World. The endophytic status of C. cateniannulata was confirmed by re-isolating it from inoculated coffee plants. Inoculation studies have further shown that C. cateniannulata is a mycoparasite of Hemileia vastatrix, as well as an entomopathogen of major coffee pests; infecting and killing Hypothenemus hampei and Leucoptera coffeella. This is the first record of C. cateniannulata from Africa, as well as an endophyte and a mycoparasite. The implications for its use as a biocontrol agent are discussed.

Metarhizium caribense sp. nov., a Novel Species of Entomopathogenic Metarhizium Fungi Associated with Weevils Impairing Coffee, Sugar Cane and Sweet Potato Cultivation.

(1) Background: Insect pathogenic fungi of the genus Metarhizium are under study and in application as highly solicited, more eco-system friendly substitutes for chemical insecticides in many countries and in different agricultural contexts. In Cuba and Florida, Metarhizium strains have previously been isolated from economically important coffee and sugar cane pests. (2) Methods: Unambiguous species delineation within the Metarhizium anisopliae species complex is methodologically challenging. Recently, a species-discriminating PCR approach has been developed based on ribosomal intergenic spacer (rIGS) sequences that covered the prominent four "PARB" species within the complex. This approach is combined here with further genetic markers and is extended to a further species. (3) Results: Metarhizium isolates from Cuba, found to be more naturally associated with the coffee berry borer, Hypothenemus hampei, were morphologically, microscopically and molecular taxonomically characterized. Multilocus sequence analysis based on 5TEF, MzIGS3 and rIGS markers delineated these weevil-associated strains from all previously established Metarhizium species. (4) Conclusions: The isolates under study represent a new fungal taxon proposed to be designated Metarhizium caribense. The rIGS-based species-discriminating diagnostic PCR is a suitable tool for the identification of new Metarhizium species and can be productively combined to approaches using further genetic markers.

Field Efficacy of Spinetoram for the Management of Coffee Berry Borer (Hypothenemus hampei).

Coffee berry borer (CBB), Hypothenemus hampei, is a damaging insect pest of coffee worldwide. CBB has recently been introduced to Hawaii, so management techniques are still being developed for sustainable and cost-efficient approaches for the effective control of this pest. Field trials were conducted to evaluate the use of spinetoram on CBB infestation and bean damage compared to Beauveria bassiana and an untreated control. Initial CBB infestations were similar, and the treatments resulted in no detectable differences in subsequent new infestations. Damage to the coffee beans was reduced by both spinetoram and B. bassiana compared to controls as the mortality of adult beetles resulting from the treatments prevented them from moving into the bean (C/D position) from the berry (A/B position). The mortality of adult beetles also prevented reproduction, subsequently reducing future CBB populations in the field. When applied to infested berries, spinetoram reduced live beetle populations in the A/B position by 73% and CBBs in the C/D position by 70% compared to the water control, whereas applications of B. bassiana reduced beetles in the C/D position by 37% but had no effect on the live A/B population. An integrated pest management program is recommended for the effective control of CBBs, and the use of spinetoram applications when adult beetles are in the A/B position appears to have potential as another management tool.

Naturally Occurring Vegetation Connectivity Facilitates Ant-Mediated Coffee Berry Borer Removal.

Vegetation connectivity is an essential aspect of the habitat complexity that impacts species interactions at local scales. However, agricultural intensification reduces connectivity in agroforestry systems, including coffee agroecosystems, which may hinder the movement of natural enemies and reduce the ecosystem services that they provide. Ants play an important role in regulating the coffee berry borer (CBB), which is the most damaging coffee pest. For arboreal ant communities, the connections between trees are important structures that facilitate ant mobility, resource recruitment, foraging success, and pest control ability. To better understand how connectivity impacts arboreal ants in coffee agroecosystems, we conducted an experiment to assess the impact of artificial (string) and naturally occurring vegetation (vines, leaves, branches) connectivity on Azteca sericeasur behavior on coffee plants. We compared ant activity, resource recruitment, and CBB removal rates across three connectivity treatments connecting coffee plants to A. sericeasur nest trees: vegetation connectivity, string, and control (not connected) treatments. We found higher rates of ant activity, resource recruitment, and CBB removal on plants with naturally occurring vegetation connections to A. sericeasur nest trees. Artificial connectivity (string) increased the rates of resource recruitment and CBB removal but to a lesser extent than vegetation connectivity. Moreover, vegetation connectivity buffered reductions in ant activity with distance from the ant nest tree. These results reinforce how habitat complexity in the form of vegetation connectivity impacts interspecific interactions at the local scale. Our results also suggest that leaving some degree of vegetation connectivity between coffee plants and shade trees can promote ant-mediated biological pest control in coffee systems.

Mathematical Model for the Biological Control of the Coffee Berry Borer Hypothenemus hampei through Ant Predation.

Coffee is a relevant agricultural product in the global economy, with the amount and quality of the bean being seriously affected by the coffee berry borer Hypothenemus hampei (Ferrari), CBB, its principal pest. One of the ways to deal with this beetle is through biological control agents, like ants (Hymenoptera: Formicidae), some of which are characterized by naturally inhabiting coffee plantations and feeding on CBB in all their life stages. Our paper considers a predator-prey interaction between these two insects through a novel mathematical model based on ordinary differential equations, where the state variables correspond to adult CBBs, immature CBBs, and ants from one species, without specifying whether preying on the CBB is among their feeding habits, in both adult and immature stages. Through this new mathematical model, we could qualitatively predict the different dynamics present in the system as some meaningful parameters were varied, filling the existing gap in the literature and envisioning ways to manage pests. Mathematically, the system's equilibrium points were determined, and its stability was studied through qualitative theory. Bifurcation theory and numerical simulations were applied to illustrate the stability of the results, which were interpreted as conditions of the coexistence of the species, as well as conditions for eradicating the pest, at least theoretically, through biocontrol action in combination with other actions focused on eliminating only adult CBBs.

Structure and Dynamics of the Gut Bacterial Community Across the Developmental Stages of the Coffee Berry Borer, Hypothenemus hampei.

The coffee berry borer (CBB); Hypothenemus hampei (Coleoptera: Curculionidae), is widely recognized as the major insect pest of coffee crops. Like many other arthropods, CBB harbors numerous bacteria species that may have important physiological roles in host nutrition, detoxification, immunity and protection. To date, the structure and dynamics of the gut-associated bacterial community across the CBB life cycle is not yet well understood. A better understanding of the complex relationship between CBB and its bacterial companions may provide new opportunities for insect control. In the current investigation, we analyzed the diversity and abundance of gut microbiota across the CBB developmental stages under field conditions by using high-throughput Illumina sequencing of the 16S ribosomal RNA gene. Overall, 15 bacterial phyla, 38 classes, 61 orders, 101 families and 177 genera were identified across all life stages, including egg, larva 1, larva 2, pupa, and adults (female and male). Proteobacteria and Firmicutes phyla dominated the microbiota along the entire insect life cycle. Among the 177 genera, the 10 most abundant were members of Ochrobactrum (15.1%), Pantoea (6.6%), Erwinia (5.7%), Lactobacillus (4.3%), Acinetobacter (3.4%), Stenotrophomonas (3.1%), Akkermansia (3.0%), Agrobacterium (2.9%), Curtobacterium (2.7%), and Clostridium (2.7%). We found that the overall bacterial composition is diverse, variable within each life stage and appears to vary across development. About 20% of the identified OTUs were shared across all life stages, from which 28 OTUs were consistently found in all life stage replicates. Among these OTUs there are members of genera Pantoea, Erwinia, Agrobacterium, Ochrobactrum, Pseudomonas, Acinetobacter, Brachybacterium, Sphingomonas and Methylobacterium, which can be considered as the gut-associated core microbiota of H. hampei. Our findings bring additional data to enrich the understanding of gut microbiota in CBB and its possible use for development of insect control strategies.

Insect herbivores benefit from horizontal gene transfer.

Evidence suggests that horizontal gene transfer (HGT) is relatively common in eukaryotes, contrary to what was previously believed. For example, insects that feed on complex sugars and neutralize, degrade, and sequester toxic secondary metabolites have recently been shown to benefit by acquiring genes through HGT.