The assassin bug venom system plays diverse roles in prey capture, defence and extra-oral digestion, but it is poorly characterised, partly due to its anatomical complexity. Here we demonstrate that this complexity results from numerous adaptations that enable assassin bugs to modulate the composition of their venom in a context-dependent manner. Gland reconstructions from multimodal imaging reveal three distinct venom gland lumens: the anterior main gland (AMG); posterior main gland (PMG); and accessory gland (AG). Transcriptomic and proteomic experiments demonstrate that the AMG and PMG produce and accumulate distinct sets of venom proteins and peptides. PMG venom, which can be elicited by electrostimulation, potently paralyses and kills prey insects. In contrast, AMG venom elicited by harassment does not paralyse prey insects, suggesting a defensive role. Our data suggest that assassin bugs produce offensive and defensive venoms in anatomically distinct glands, an evolutionary adaptation that, to our knowledge, has not been described for any other venomous animal.

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The assassin bug Pristhesancus plagipennis produces two distinct venoms in separate gland lumens

Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) is an obligate zoophytophagous predator because its population can be maintained in the laboratory when fed on both prey and plants. We evaluated ultrastructural changes in the midgut digestive cells of adult B. tabidus, subjected to different treatments (starvation or feeding on plant material and prey) for different periods. Their midguts were dissected, divided into anterior, medium and posterior sections, processed, and analyzed with light and transmission electron microscopy. The anterior region of the midgut of B. tabidus, starved or fed on eucalyptus leaves, contained no glycogen. B. tabidus fed on plant material showed multivesicular bodies in this region, and spherocrystals after 6 h of feeding on prey. The microvilli of the medium midgut were longer than those of the anterior and posterior midgut. The posterior midgut differed from the other two regions by an abundance of mitochondria, rough endoplasmatic reticulum and double me...

https://bioone.org/journals/annals-of-the-entomological-society-of-america/volume-102/issue-1/008.102.0113/Ultrastructure-of-the-Digestive-Cells-in-the-Midgut-of-the/10.1603/008.102.0113.pdf

Ultrastructure of the Digestive Cells in the Midgut of the PredatorBrontocoris Tabidus (Heteroptera: Pentatomidae) After Different Feeding Periods on Prey and Plants

Prey digestion in the midgut of the predatory bug Podisus nigrispinus (Hemiptera: Pentatomidae)

The piercing-sucking mouthparts of the true bugs (Insecta: Hemiptera: Heteroptera) have allowed diversification from a plant-feeding ancestor into a wide range of trophic strategies that include predation and blood-feeding. Crucial to the success of each of these strategies is the injection of venom. Here we review the current state of knowledge with regard to heteropteran venoms. Predaceous species produce venoms that induce rapid paralysis and liquefaction. These venoms are powerfully insecticidal, and may cause paralysis or death when injected into vertebrates. Disulfide-rich peptides, bioactive phospholipids, small molecules such as N,N-dimethylaniline and 1,2,5-trithiepane, and toxic enzymes such as phospholipase A2, have been reported in predatory venoms. However, the detailed composition and molecular targets of predatory venoms are largely unknown. In contrast, recent research into blood-feeding heteropterans has revealed the structure and function of many protein and non-protein components that facilitate acquisition of blood meals. Blood-feeding venoms lack paralytic or liquefying activity but instead are cocktails of pharmacological modulators that disable the host haemostatic systems simultaneously at multiple points. The multiple ways venom is used by heteropterans suggests that further study will reveal heteropteran venom components with a wide range of bioactivities that may be recruited for use as bioinsecticides, human therapeutics, and pharmacological tools.

/pdf/venoms-of-heteropteran-insects-a-treasure-trove-of-diverse-3vd7iz4yh9.pdf

Venoms of Heteropteran Insects: A Treasure Trove of Diverse Pharmacological Toolkits

Zoophytophagous insects can feed on a variety of prey, plants and plant products. By studying the interactions between predatory hemipterans and plants harbouring the prey of these insects, scientists have started to establish two potential outcomes: (1) positive effects like the enhancement of their life history characteristics by acquiring plant contents; and (2) negative effects mediated by plant resistance to herbivores or prey ingesting secondary plant metabolites. Despite this research, there is a lack of information about the feeding sites of predatory hemipterans on their host plants, what they ingest from plants, and whether they cause damage to their host plants. The results presented here indicate that the xylem is one of the feeding sites of predatory hemipterans on plants. The dissection of predators that fed on plants with marked vessels and testing insects for the presence of Cry protein constitutively expressed in the cytoplasm of plant cells revealed that bugs are not able to acquire cytoplasm contents from the plant cell. In addition, we demonstrate that systemic insecticide circulating inside plants from soil applications contaminates these predators. Our results are discussed in the context of zoophytophagous feeding behaviour exhibited by predatory hemipterans and the use of systemic insecticides for the conservation of natural enemies. This interaction contradicts the concept of ecological selectivity obtained for natural enemies through the placement of systemic insecticide in the soil as a selective method of deploying chemical control and predatory hemipteran conservation within the integrated pest management framework.

Zoophytophagous pentatomids feeding on plants and implications for biological control

The aim of this work was to study the feeding habits of the predator Brontocoris tabidus (Heteroptera: Pentatomidae) analyzing the salivary gland complex (SGC). The SGC was dissected and subjected to histological analyses and biochemical assays. Results showed that a pair of bilobed principal salivary glands and one pair of tubular accessory salivary glands form the SGC and different parts of salivary gland synthesizes similar substances. Lipases, a-amylase and trypsin-like enzymes were detected at both lobes of the principal salivary gland. These data together with observations related to the predator's diet suggested that it could be considered an obligate zoophytophagous.

/pdf/biochemical-and-morphological-aspects-of-salivary-glands-of-55s9rycrvc.pdf

Biochemical and morphological aspects of salivary glands of the predator Brontocoris tabidus (Heteroptera: Pentatomidae)

The invasive mealybug Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) is a plant feeding insect believed to be native to Southern Asia or Australia. This mealybug has become established in many regions throughout the world (including the Caribbean and North America) in the past 100 years and is currently expanding its range in South America. Because this insect is of concern as a potential pest of many plant species, this review is provided to summarize knowledge of M. hirsutus based on past research that may be most useful for addressing the current invasion of South America by the species, and to identify gaps in information that may need to be addressed to inhibit the spread of the insect and improve management methods for this and similar organisms. In most areas into which M. hirsutus has expanded its range it is commonly suppressed by native or introduced natural enemies. Therefore, besides preventing introduction, establishment and spread of this potential pest, efforts should be made to determine if natural enemies of M. hirsutus are present in areas of concern (i.e., where the mealybug may be introduced and become established). Such information will enable determination of the need for introduction or augmentation of biological control agents in response to possible entry and establishment of the mealybug in new areas. Methods developed in response to the recent invasion of the Caribbean and North America by M. hirsutus may serve as models for addressing the threat of this and similar invasive pests in South America and elsewhere.

The invasive mealybug Maconellicoccus hirsutus: lessons for its current range expansion in South America and invasive pest management in general

Summary Litchi (Litchi chinensis Sonn.) is cultivated in subtropical and tropical regions, and in Brazil, commercial orchards began in the 1970–80s. The litchi erinose mite (LEM), Aceria litchii (Keifer) (Acari: Eriophyidae), is a pest of litchi worldwide. In Brazil, LEM was first reported in this crop in Sao Paulo State in 2008, and Espirito Santo is the second Brazilian state with infestation of this mite discovered in a 18-year-old orchard of 150 plants of the litchi cultivar ‘Bengal’. Cultural and chemical measures for LEM management are presented, and this is the first range expansion of LEM into Espirito Santo State, Brazil.

https://bioone.org/journals/florida-entomologist/volume-97/issue-2/024.097.0276/Range-Expansion-of-the-Litchi-Erinose-Mite-Aceria-litchii-Acari/10.1653/024.097.0276.pdf

José Salazar Zanuncio

Papers

Biochemical and morphological aspects of salivary glands of the predator Brontocoris tabidus (Heteroptera: Pentatomidae)

The invasive mealybug Maconellicoccus hirsutus: lessons for its current range expansion in South America and invasive pest management in general

Range Expansion of the Litchi Erinose Mite Aceria litchii (Acari: Eriophyidae) in Brazil

Flutuação populacional de coleoptera em flutuação populacional de coleoptera em