Observations on the Association between Some Buprestid and Cerambycid Beetles and Black Frankincense Resin Inducement

Samburu resin harvesters in northern Kenya maintain that frankincense resin flow from Boswellia neglecta and Commiphora confusa is induced by insect larval activity. Observations on the insects’ larval behaviour support these claims. During the frankincense harvest, buprestid beetle larvae, identified as a Sphenoptera species, are found under B. neglecta resin, eating the monoterpene-rich inner bark, which apparently stimulates the trees to produce copious amounts of fresh resin. The same behaviour was observed with cerambycid beetle larvae, identified as Neoplocaederus benningseni Kolbe, on C. confusa trees. Remarkably, these insects have developed the capacity to digest the resin-saturated inner bark and overcome the toxic, repellent characteristics of oleo-monoterpenes. The frankincense resin also appears to act as a protective covering during the insects’ larval and pupal stages. Excessive tree damage was not noted from these insect invasions. Even though the tree species are from different genera, the resin produced by both is black, with a very similar aromatic chemical profile. The question thus arises as to whether the larval feeding behaviour of these beetle species has an influence, not only on the physical appearance but also on the chemical composition of the resins.

Areawide management of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), using selected cover crop plants

Background Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a migratory moth that annually migrates northward each spring from sites in southern Florida and southern Texas. This caterpillar pest feeds on and damages row, turf and vegetable crops in the eastern and central U.S. Before migrating in spring, it feeds on cover crops in central and eastern Florida and expands its populations. Our objective was to use multi-year studies to compare fall armyworm populations that develop in cover crop plants. Methods A series of field experiments and a laboratory feeding study were conducted to compare infestation and feeding and of fall armyworm on different cover crop plants. Field experiments had plots planted with corn (Zea mays L.), sorghum-sudangrass [Sorghum bicolor (L.) Moench], a standard cover crop in Florida, and two alternative cover crops, sunn hemp (Crotalaria juncea L.) and cowpea [Vigna unguiculata (L.) Walpers spp. unguiculata]. Another trial compared populations in sorghum-sudangrass and in mixtures of sorghum-sudangrass with buckwheat (Fagopyrum esculentum Moench) or pearl millet (Cenchrus americanus (L.) Morrone). Fall armyworm larvae were fed and allowed to develop on different sunn hemp germplasm in a laboratory trial. Results Field populations of fall armyworm were highest on corn, followed by sorghum-sudangrass. Sunn hemp and cowpea had larval populations 70–96% less than on sorghum-sudangrass, suggesting replacement of this cover crop with either plant species might help reduce areawide populations of resident or migratory fall armyworm. Larvae collected from cover crop plots had parasitism levels that averaged 30%, with Chelonus insularis (Hymenoptera: Braconidae) emerging as the most commonly-collected species. Larval feeding on different sunn hemp germplasm lines resulted in no difference in weight gain. Conclusions Replacing sorghum-sudangrass with sunn hemp varieties or germplasm should be acceptable as a replacement cover crop for areawide management of fall armyworm.

Root-Associated Entomopathogenic Fungi Modulate Their Host Plant’s Photosystem II Photochemistry and Response to Herbivorous Insects

The escalating food demand and loss to herbivores has led to increasing interest in using resistance-inducing microbes for pest control. Here, we evaluated whether root-inoculation with fungi that are otherwise known as entomopathogens improves tomato (Solanum lycopersicum) leaflets’ reaction to herbivory by Spodoptera exigua (beet armyworm) larvae using chlorophyll fluorescence imaging. Plants were inoculated with Metarhizium brunneum or Beauveria bassiana, and photosystem II reactions were evaluated before and after larval feeding. Before herbivory, the fraction of absorbed light energy used for photochemistry (ΦPSII) was lower in M. brunneum-inoculated than in control plants, but not in B. bassiana-inoculated plants. After herbivory, however, ΦPSII increased in the fungal-inoculated plants compared with that before herbivory, similar to the reaction of control plants. At the same time, the fraction of energy dissipated as heat (ΦNPQ) decreased in the inoculated plants, resulting in an increased fraction of nonregulated energy loss (ΦNO) in M. brunneum. This indicates an increased singlet oxygen (1O2) formation not detected in B. bassiana-inoculated plants, showing that the two entomopathogenic fungi differentially modulate the leaflets’ response to herbivory. Overall, our results show that M. brunneum inoculation had a negative effect on the photosynthetic efficiency before herbivory, while B. bassiana inoculation had no significant effect. However, S. exigua leaf biting activated the same compensatory PSII response mechanism in tomato plants of both fungal-inoculated treatments as in control plants.

Infestation of the gall midge Dasineura oleae provides first evidence of induced plant volatiles in olive leaves

In this study, we present the first characterization of herbivore-induced plant volatiles (HIPVs) released from infested olive leaves. The gall midge Dasineura oleae is a specific pest of Olea europaea and endemic of the Mediterranean Basin, an area in which severe outbreaks currently occurred. Little is known about the damage caused by the pest and the relationship with its host. Since gall formation and larval feeding activity may lead to the release of specific plant volatile compounds, we investigated the volatile profiles emitted from infested plants compared with healthy plants under both laboratory and field conditions. Additionally, the volatiles emitted from mechanically damaged plants were considered. A blend of 12 volatiles was emitted from olive trees infested by D. oleae. Of these, β-copaene, β-ocimene, cosmene, unknown 1 and unknown 3 were found to be exclusively emitted in infested plants. The emission of germacrene-D, (E,E)-α-farnesene, and (Z,E)-α-farnesene, α-copaene, (E)-4,8-dimethylnona-1,3,7-triene, (E)-β-guaiene and heptadecane significantly increased in infested trees. Linalool, β-copaen-4-α-ol, β-bourbonene, β-cubebene, β-elemene, β-copaene and δ-amorphene were found only in the field trial and showed differences depending on the level of infestation and the plant stage. (Z)-3-Hexenol, (E)-4-oxohen-2-enal, and 2-(2-butoxyethoxy)-ethanol, were exclusively emitted from the leaves after mechanical damage. In a field trial in Italy, we also demonstrated spring synchronization between adults of D. oleae and O. europaea trees. Analyses of morphoanatomical malformations of gall leaves showed that tissue alterations occur at the spongy parenchyma causing an increase of the leaf blade thickness. We speculate that tissue alterations may lead to HIPV release, in turn potentially attracting D. oleae natural enemies.

In search for the unlikely: Leaf-mining caterpillars (Gracillariidae, Lepidoptera) from Upper Cretaceous and Eocene ambers

Fossil leaf-mining caterpillars from amber are firstly described as the new species Phyllocnistis cretacea from Upper Cretaceous Myanmar amber and Phyllonorycter inopinata from Eocene Baltic amber. Both show typical traits of leaf-miners, and specifically, of later instars of caterpillars of their respective genera. The findings give further evidence for these being quite old and conservative genera of Gracillariidae. These are basal Ditrysia which retained the larval feeding and mining live mode. The findings also represent direct fossil evidence of individual stages of hypermetamorphosis known from extant Gracillariidae. The finds from the Upper Cretaceous and their putative identifications give direct evidence for a minimal geological age for the genus Phyllocnistis (Phyllocnistinae) and, by indirect conclusion based on their divergence, also for the genus Phyllonorycter in a sister clade (Lithocolletinae). It also predates mining habit closer to the time of radiation of their angiospermous host plants.

Responses to larval herbivory in the phenylpropanoid pathway of Ulmus minor are boosted by prior insect egg deposition

Main conclusion Elms, which have received insect eggs as a ‘warning’ of larval herbivory, enhance their anti-herbivore defences by accumulating salicylic acid and amplifying phenylpropanoid-related transcriptional and metabolic responses to hatching larvae. Abstract Plant responses to insect eggs can result in intensified defences against hatching larvae. In annual plants, this egg-mediated effect is known to be associated with changes in leaf phenylpropanoid levels. However, little is known about how trees—long-living, perennial plants—improve their egg-mediated, anti-herbivore defences. The role of phytohormones and the phenylpropanoid pathway in egg-primed anti-herbivore defences of a tree species has until now been left unexplored. Using targeted and untargeted metabolome analyses we studied how the phenylpropanoid pathway of Ulmus minor responds to egg-laying by the elm leaf beetle and subsequent larval feeding. We found that when compared to untreated leaves, kaempferol and quercetin concentrations increased in feeding-damaged leaves with prior egg deposition, but not in feeding-damaged leaves without eggs. PCR analyses revealed that prior insect egg deposition intensified feeding-induced expression of phenylalanine ammonia lyase (PAL), encoding the gateway enzyme of the phenylpropanoid pathway. Salicylic acid (SA) concentrations were higher in egg-treated, feeding-damaged leaves than in egg-free, feeding-damaged leaves, but SA levels did not increase in response to egg deposition alone—in contrast to observations made of Arabidopsis thaliana. Our results indicate that prior egg deposition induces a SA-mediated response in elms to feeding damage. Furthermore, egg deposition boosts phenylpropanoid biosynthesis in subsequently feeding-damaged leaves by enhanced PAL expression, which results in the accumulation of phenylpropanoid derivatives. As such, the elm tree shows similar, yet distinct, responses to insect eggs and larval feeding as the annual model plant A. thaliana.

Investigation of Transovarial Transmission of Bartonella henselae in Rhipicephalus sanguineus sensu lato Ticks Using Artificial Feeding

Bartonella henselae is a slow-growing, Gram-negative bacterium that causes cat scratch disease in humans. A transstadial transmission of the bacteria from larvae to nymphs of Rhipicephalus sanguineus sensu lato (s.l.) ticks, suspected to be a potential vector of the bacteria, has been previously demonstrated. The present study aims to investigate transovarial transmission of B. henselae from R. sanguineus s.l. adults to their instars. Adult ticks (25 males and 25 females) were fed through an artificial feeding system on B. henselae-infected goat blood for 14 days, and 300 larvae derived from the experimentally B. henselae-infected females were fed on noninfected goat blood for 7 days. Nested PCR and culture were used to detect and isolate B. henselae in ticks and blood samples. Bartonella henselae DNA was detected in midguts, salivary glands, and carcasses of the semi-engorged adults and pooled tick feces (during feeding and post-feeding periods). After the oviposition period, B. henselae DNA was detected in salivary glands of females (33.3%), but not in pooled eggs or larvae derived from the infected females. However, B. henselae DNA was detected by nested PCR from the blood sample during larval feeding, while no viable B. henselae was isolated by culture. According to our findings, following infected blood meal, B. henselae could remain in the tick midguts, move to other tissues including salivary glands, and then be shed through tick feces with limited persistency. The presence of bacterial DNA in the blood during larval feeding shows the possibility of transovarial transmission of B. henselae in R. sanguineus s.l. ticks.

Elucidation of Triadic Relationship Among Light Environment, Host Plant Quality, and Feeding Behavior of Zizeeria maha (Kollar) (Lepidoptera: Lycaenidae) IN Oxalis corniculata L. (Oxalidales: Oxalidaceae)

In the dynamics of light-plant-insect interaction, the light affects plant metabolisms which may directly influence the production of defensive secondary metabolites and may consequently alter the feeding behavior of herbivores. The present study aimed to investigate the triadic interactions by using Oxalis corniculata L. (Oxalidales: Oxalidaceae) and its specialist herbivore, Zizeeria maha (Kollar) (Lepidoptera: Lycaenidae), in relation to the light intensity of plant habitats and physicochemical properties of the plants which would affect the larval feeding behavior of Z. maha. Firstly, leaves of O. corniculate in the field with seven different light conditions were collected. A part of which was subjected to chemical analyses, and the rest was fed to Z. maha larvae to evaluate growth and feeding activity; larval period, death rate, weight, amount of consumption, and amount of frass were measured to calculate the relative growth rate, approximate digestion rate, and relative consumption rate. Secondly, light/shade mock environment test tests were conducted with laboratory-grown O. corniculata. The results under both field and laboratory conditions showed positive effects of light intensity on the production of the defensive compound, oxalic acid, in the plants. Furthermore, the larval feeding activity was higher when fed with leaves in higher light intensities. These results relate to our previous study that demonstrated oxalic acid stimulates the feeding of Z. maha larvae. Thus, the triadic interaction among light, O. corniculata, and Z. maha larvae could be explained by the light-driven up-regulated production of oxalic acid positively influenced the larval feeding.

Effectiveness of Entomopathogenic Fungi on Immature Stages and Feeding Performance of Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) Larvae

Maize is a major staple crop in China, and the sustainable productivity of this primary crop has been recently threatened by fall armyworm (FAW), Spodoptera frugiperda, invasion. The five fungal isolates, Aspergillus sp. BM-3 and SE-2-1, Cladosporium tenuissimum SE-10, Penicillium citrinum CTD-24, and Beauveria bassiana ZK-5 were assessed for their efficacy in causing mortality against first to sixth instar eggs and neonate larvae seven days post-treatment, and their effects on the feeding performance of sixth instar S. frugiperda larvae at 48 h post-treatment at three concentrations (1 × 106, 1 × 107, and 1 × 108 conidia mL−1) were also assessed. The six instar S. frugiperda larvae were not susceptible to the five tested fungal isolates. However, B. bassiana ZK-5 caused the highest egg mortality of 40, 70, and 85.6% at 1 × 106, 1 × 107, and 1 × 108 conidia mL−1, respectively, followed by P. citrinum CTD-24 (30.6, 50, and 75.6%) and C. tenuissimum SE-10 (25.6, 40, and 55.6%). In addition, B. bassiana ZK-5 caused the highest neonate mortality of 54.3% at 1 × 108 conidia mL−1. B. bassiana ZK-5 and P. citrinum CTD-24 caused cumulative mortality, including 93.3 and 83.3% mortality of eggs and neonates, respectively, at 1 × 108 conidia mL−1. Furthermore, B. bassiana ZK-5 reduced the feeding efficacy of first to third instar S. frugiperda larvae by 66.7 to 78.6%, while P. citrinum CTD-24 and C. tenuissimum SE-10 reduced larval feeding by 48.3 to 57.1% at 1 × 108 conidia mL−1. However, these fungal isolates were less potent in reducing the feeding activity of fourth to sixth instar S. frugiperda larvae (>46% with B. bassiana at 48 h post-treatment). The tested fungal isolates could play an essential role as microbial biopesticides in suppressing the S. frugiperda population in China after further investigations on their efficacy are obtained in the field.

Uji Efektivitas Metabolit Sekunder Jamur Simplicillium sp. terhadap Spodoptera frugiperda J.E. Smith di Laboratorium

This research aims to determine the effect of the secondary metabolites of the fungi Simplicillium sp. on mortality, larval feeding capacity, larval growth, percentage of pupae and imagos, fecundity and fertility, secondary metabolites of the fungi Simplicillium sp. which effectively kills Spodoptera frugiperda. This research was conducted in the Plant Protection Laboratory of Agriculture Faculty, Jenderal Soedirman University, Purwokerto from October 2020 until January 2021. The method used in this research was a factorial randomized block (RBD) with two factors. The first factor is the concentration of secondary metabolite of the fungi Simplicillium sp. consisting of control (K0), 10% concentration (K1), 20% concentration (K2), 30% concentration (K3); and a synthetic insecticide with an active ingredient Emmamectin benzoate and Lufenuron 1 ml/l (K4). The second factor is the application method which consists of the spraying method on the larvae (A1) and the feed immersion method (A2). The observed parameters were mortality, feeding capacity, growth time, percentage of pupae and imagos formed, fecundity and fertility, and effective concentration. The result showed that: 1) secondary metabolite of the fungi Simplicillium sp. with a concentration of 20 percent larvae spraying method caused larvae mortality by 36.67 percent and the food immersion method caused larvae mortality by 45.00 percent, and decreased feeding activity by 26.12 percent; 2) secondary metabolite of the fungi Simplicillium with a concentration of 20 percent was able to inhibit the growth of larvae by 3.83 percent, pupae by 5,40 percent and imagos by 14.19 percent, reduced the number of pupae and imagos formed by 49.17 percent and 37.33 percent, and reduced fertility at a concentration of 10 percent by 11.30 percent; 3) secondary metabolite of the fungi Simplicillium sp. has not been effectively used as a control for S. frugiperda since it has an efficacy value of less than 80 percent.