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Zoophytophagous predators play an important, though sometimes controversial, role in pest management programs in different crops. In tomato crops, damage caused by phytophagy of the mirid Nesidiocoris tenuis has mainly been reported at high predator population levels or when prey is scarce. Previous research has focused on predator/prey ratios, stylet morphology and saliva composition to explain plant damage by N. tenuis. In this study, we investigated the behavioral and mechanical components of the damage. For this, we compared the feeding behaviors of males, females and fifth-instar nymphs of N. tenuis. Additionally, we investigated the type of stylet activities performed by each stage while probing in plant tissue, using the electrical penetration graph technique (EPG). Furthermore, stylectomy was performed and plant histology studied with the aim to correlate the feeding activities observed in the EPG recordings with stylet tip positions in specific tissues of the leaf petioles. Behavioral observations during a 30-min period showed that nymphs probed more frequently (38.6 ± 1.5 probes) than males and females (25.3 ± 1.1 and 24.3 ± 1.1 probes, respectively). Similarly, nymphs spent a higher proportion of time (656.0 ± 67.6 s) feeding on tomato apical sections compared to males and females (403.0 ± 48.8 s and 356.0 ± 43.7 s, respectively). The EPG recordings during 5 h indicated that cell-rupturing was the main stylet activity for all insect stages, and that fifth-instar nymphs spent a higher proportion of time on cell-rupturing events compared to adults. The histological studies revealed a trend of N. tenuis for the tissues within the vascular semi-ring. The stylet tips were found both in the vascular bundles and in the parenchyma of the interfascicular region. The findings of this study confirm an important role of fifth-instar nymphs feeding behavior in the damage potential of N. tenuis. Moreover, the increased time spent on cell rupturing behaviour suggests that stylet laceration and enzymatic maceration of the saliva occurring during this event might greatly contribute to the inflicted damage. A comprehensive understanding of the interactions of N. tenuis with the plant, at both the behavioral and mechanical levels, might shed light on new approaches to minimize its damage potential to tomato while maintaining its benefits as biocontrol agent.

OBJECTIVES: Edible insects are considered as an alternative source of proteins, but in addition are also rich sources of minerals. However, no studies have investigated the bioavailability of minerals from edible insects in humans. House cricket (Acheta domesticus) is an edible insect species that is commonly consumed in low and middle income countries where the prevalence of iron deficiency and anaemia is relatively high. We aimed to assess the fractional iron absorption of iron from house crickets in humans after addition to either a refined (low-phytate) or a whole meal (high-phytate) maize porridge meal. A second objective was to assess the fractional iron absorption from maize porridge meals when crickets were added. METHODS: A single blind randomized cross-over trial was conducted. We recruited 24 females (18–30 years) with serum ferritin

To investigate the role of inducible linalool in Arabidopsis-insect interactions, the FaNES1 linalool synthase (LIS) cDNA from strawberry with plastid targeting and a synthetic intron (LIS') was placed under the control of the wound inducible proteinase inhibitor 2 (PI2) promoter from potato. The construct pBin-PPI2-LIS' was transformed to Arabidopsis thaliana ecotype Columbia 0. Kanamycin resistant T0 seedlings were confirmed for the presence and transcription of the LIS' gene by PCR analysis on genomic DNA and by RT-PCR analysis on RNA. Genomic and RT-PCR products were sequenced to confirm correct splicing of the synthetic intron. The expression of active linalool synthase by the PPI2-LIS' gene construct in the transgenic lines was assessed by measuring linalool emission using solid phase micro-extraction (SPME) GC-MS measurements after induction with methyl jasmonate. Among 30 tested independent T2 transgenic lines, 10 exhibited linalool production. Linalool expression could be induced by methyl jasmonate treatment, but not by diamondback moth larvae.

Summary Background Many species of mosquitoes, including the major malaria vector Anopheles gambiae , utilize carbon dioxide (CO 2 ) and 1-octen-3-ol as olfactory cues in host-seeking behaviors that underlie their vectorial capacity. However, the molecular and cellular basis of such olfactory responses remains largely unknown. Results Here, we use molecular and physiological approaches coupled with systematic functional analyses to define the complete olfactory sensory map of the An. gambiae maxillary palp, an olfactory appendage that mediates the detection of these compounds. In doing so, we identify three olfactory receptor neurons (ORNs) that are organized in stereotyped triads within the maxillary-palp capitate-peg-sensillum population. One ORN is CO 2 -responsive and characterized by the coexpression of three receptors that confer CO 2 responses, whereas the other ORNs express characteristic odorant receptors (AgORs) that are responsible for their in vivo olfactory responses. Conclusions Our results describe a complete and highly concordant map of both the molecular and cellular olfactory components on the maxillary palp of the adult female An. gambiae mosquito. These results also facilitate the understanding of how An. gambiae mosquitoes sense olfactory cues that might be exploited to compromise their ability to transmit malaria.

The effect of a single blood meal on the host-seeking response of Anopheles gambiae was investigated in the laboratory using a behavioural bioassay, whereas possible changes at the chemosensory level were monitored using electroantennogram recording (EAG). To avoid the possible confounding effect of body size, mosquitoes of a large size class only were used. Five-day old female mosquitoes were given a blood meal on a human arm and exposed to the emanations of a human hand in an olfactometer at 3, 24, 40, 48 and 72 h following the meal and their behaviour and EAG response to host stimuli were compared with that of unfed mosquitoes (controls) of corresponding age. During egg development, mosquitoes had access to glucose and an oviposition tray. The ovarian development of blood-fed mosquitoes that responded to host odours was compared with that of blood-fed mosquitoes that had not been exposed to host odours. The EAG response of blood-fed and control mosquitoes to host odour was examined upon stimulation with air led over incubated human sweat, hexanoic acid, indole and geranyl acetone. EAGs were recorded at times after a blood meal corresponding with those used in the behavioural experiment. There was no host-seeking response at 3 and 24 h post blood meal (pbm). Seven percent of the mosquitoes responded to human emanations 40-h pbm, 27% at 48 h and 68% at 72 h following a blood meal. The average response of controls to host stimuli varied from 35 (at t=40 h) to 67%. There was no ovarian development in the unfed group of mosquitoes. Of the mosquitoes that responded to host odour 48 h pbm, 12.5% (n=5) had ovaries in Christophers' stage IV and the remainder in stage V. Of the mosquitoes that responded 72 h pbm, 66.7% (n=94) had ovaries in stage V and 31.2% (n=44) had recently oviposited. Maximum EAG amplitudes recorded from blood-fed and control mosquitoes were similar for mosquitoes in Christophers' stages I-III, whereas in stage IV EAG amplitudes recorded from the blood-fed group were significantly lower than those of the corresponding control group in response to headspace of incubated human sweat and to indole. The results show that there was a strong inhibition of host seeking in An. gambiae for a period of at least 40 h following a blood meal. Host-seeking returned to pre-blood meal levels 72-h post feeding and was associated with egg maturation. The inhibition of host-seeking behaviour was accompanied by an inhibition of olfactory sensitivity to headspace of incubated sweat and indole just before the resumption of the host-seeking response. The implications of these findings for mosquito surveillance with host odours are discussed.