Mosquito host-seeking diel rhythm and chemosensory gene expression is affected by age and Plasmodium stages

Malaria parasites can affect vector-related behaviours, increasing transmission success. Using Anopheles gambiae and Plasmodium falciparum, we consider the effect of interaction between infection stage and vector age on diel locomotion in response to human odour and the expression of antennal chemosensory genes. We identified age-dependent behavioural diel compartmentalisation by uninfected females post-blood meal. Infection disrupts overall and diel activity patterns compared with age-matched controls. In this study, mosquitoes carrying transmissible sporozoites were more active, shifting activity periods which corresponded with human host availability, in response to human odour. Older, uninfected, blood-fed females displayed reduced activity during their peak host-seeking period in response to human odour. Age- and infection stage-specific changes in odour-mediated locomotion coincide with altered transcript abundance of select chemosensory genes suggesting a possible molecular mechanism regulating the behaviour. We hypothesize that vector-related behaviours of female mosquitoes are altered by infection stage and further modulated by the age post-blood meal of the vector. Findings may have important implications for malaria transmission and disease dynamics

Composition of strawberry floral volatiles and their effects on behavior of strawberry blossom weevil, anthonomus rubi

The strawberry blossom weevil (SBW), Anthonomus rubi, is a major pest in strawberry fields throughout Europe. Traps baited with aggregation pheromone are used for pest monitoring. However, a more effective lure is needed. For a number of pests, it has been shown that the attractiveness of a pheromone can be enhanced by host plant volatiles. The goal of this study was to explore floral volatile blends of different strawberry species (Fragaria x ananassa and Fragaria vesca) to identify compounds that might be used to improve the attractiveness of existing lures for SBW. Floral emissions of F. x a. varieties Sonata, Beltran, Korona, and of F. vesca, were collected by both solid-phase microextraction (SPME) and dynamic headspace sampling on Tenax. Analysis by gas chromatography/mass spectrometry showed the floral volatiles of F. x ananassa. and F. vesca were dominated by aromatic compounds and terpenoids, with 4-methoxybenzaldehyde (p-anisaldehyde) and α-muurolene the major compounds produced by the two species, respectively. Multi-dimensional scaling analyses separated the blends of the two species and explained differences between F. vesca genotypes and, to some degree, variation between F. x ananassa varieties In two-choice behavioral tests, SBW preferred odors of flowering strawberry plants to those of non-flowering plants, but weevils did not discriminate between odors from F. x ananassa and F. vesca flowering plants. Adding blends of six synthetic flower volatiles to non-flowering plants of both species increased the preference of SBW for these over the plants alone. When added individually to non-flowering plants, none of the components increased the preference of SBW, indicating a synergistic effect. However, SBW responded to 1,4-dimethoxybenzene, a major component of volatiles from F. viridis, previously found to synergize the attractiveness of the SBW aggregation pheromone in field studies

Phyllonorycter strigulatella (Lien. and Z.) ir Ph. sorbi (Frr.) (Lepidoptera, Gracillariidae) patelių feromono skleidimo elgesys temperatūrai kintant paros metu

The pheromone release postures of virgin Phyllonorycter strigulatella and Ph. sorbi females were very similar to those of other species of the same genus with antennae held close to the wings, which were slightly spread and lowered, the abdominal tip dorsally curved and the distal segments extended. In both species with equal sex ratios, one peak of signalling activity was registered 0.5 h after the light had been put on and when 84% of Ph. strigulatella and 90% of Ph. sorbi individuals were active. The high pheromone release behaviour with 50% active females lasted for two hours. The calling activity of the group of females was about 6 h/day for both species. The total period of calling activity of an individual female lasted for 131 ± 62 min (mean ± SD) and 145 ± 73 min a day for Ph. strigulatella and Ph. sorbi respectively. The occurrence of one signalling peak per day in the species with equal sex ratios as found in Ph. strigulatella and Ph. sorbi, supported the hypothesis that pheromone release activity with a clear presence of two activity peaks during a photophase could be adaptive for species with a sex ratio strongly shifted towards females, as in Ph. junoniella

Phyllonorycter strigulatella (Lien. and Z.) ir Ph. sorbi (Frr.) (Lepidoptera, Gracillariidae) patelių feromono skleidimo elgesys temperatūrai kintant paros metu

The pheromone release postures of virgin Phyllonorycter strigulatella and Ph. sorbi females were very similar to those of other species of the same genus with antennae held close to the wings, which were slightly spread and lowered, the abdominal tip dorsally curved and the distal segments extended. In both species with equal sex ratios, one peak of signalling activity was registered 0.5 h after the light had been put on and when 84% of Ph. strigulatella and 90% of Ph. sorbi individuals were active. The high pheromone release behaviour with 50% active females lasted for two hours. The calling activity of the group of females was about 6 h/day for both species. The total period of calling activity of an individual female lasted for 131 ± 62 min (mean ± SD) and 145 ± 73 min a day for Ph. strigulatella and Ph. sorbi respectively. The occurrence of one signalling peak per day in the species with equal sex ratios as found in Ph. strigulatella and Ph. sorbi, supported the hypothesis that pheromone release activity with a clear presence of two activity peaks during a photophase could be adaptive for species with a sex ratio strongly shifted towards females, as in Ph. junoniella

Phyllonorycter obandai Prins & Mozūraitis, 2006, new species

Phyllonorycter obandai, new species Figs. 4, 8, 9 Diagnosis. This new species is clearly distinguishable by its wing pattern and male genitalia from P. loxozona (Meyrick, 1936), described from Uganda, but which could occur in Kenya also. Its wing pattern is comparable to that of P. rhynchosiae (Vári, 1961) and its male genitalia to those of P. brachylaenae (Vári, 1961). The last two species are known from South Africa. P. obandai is easily distinguishable from P. loxozona (Fig. 1) by the following differences in wing pattern: The forewing of P. obandai has a long basal streak reaching 7 ¼ of wing; in P. loxozona the streak is short and oblique. The forewing of P. loxozona has two very clearly defined white fascia; in P. obandai only strigulae are present. The forewing of P. l o x o z o n a possesses two opposite triangular spots at 3 / 4 finely edged with blackish interiorly; in P. obandai the 3 rd costal is situated just before the apex and not edged. This species is distinguishable from P. brachylaenae (Fig. 2) by the longer basal streak and the absence of two transverse fasciae, which are clearly defined in the forewing of P. brachylaenae. The new species is distinguished from the superficially similar P. rhynchosiae (Fig. 3) by its smaller size, the brighter golden ground coloration of the forewing, the longer basal white streak reaching to 1 / 4 of the forewing, the second dorsal strigula that reaches only the middle of the wing, and the absence of an ochreous­fuscous patch on the outer side of the tibia. In this group it is advisable to examine the genitalia for a correct identification of the species. P. obandai (Fig. 8, 9) is distinguishable from P. loxozona (Fig. 5) by clear differences in the form of the valva, the saccus length, and the form of the 8 th sternite. The valva of P. loxozona is long, slender and curved; in P. obandai it is enlarged in the apical third and rounded. The saccus of P. l o x o z o n a is short, pointed; in P. obandai it is almost twice as long as valva, slender bearing a small apical process. The 8 th sternite of P. loxozona is triangular and bifurcated at its apex; in P. obandai it is semicircular. The following are differences between the male genitalia of P. obandai (Fig. 8, 9) and P. brachylaenae (Fig. 6): The costal and dorsal sides of the valva of P. brachylaenae are more or less parallel throughout; the valva of P. obandai is enlarged in the apical third and much more rounded. The valva of P. brachylaenae has a conspicuous ridge from the centre of the costa towards the centre of the outer margin; this ridge is missing or only very weekly indicated in P. obandai. The width/length of the valva in P. brachylaenae = 0.225; P. obandai = 0.294. The valval length/aedeagus length in P. brachylaenae = 0.8; in P. obandai = 0.47 (the aedoeagus in P. obandai is much longer in comparison to the valval length). The new species is distinguishable from P. r h y n c h o s i a e (Fig. 7) by the characteristic rounded caudal margin of the valvae lacking any defined projection.Published as part of Prins, Jurate De & Mozūraitis, Raimondas, 2006, A new species of Phyllonorycter (Lepidoptera: Gracillariidae) from Kenya discovered by using the sex attractant Z 8 ­ tetradecen­ 1 ­ yl acetate, pp. 55-68 in Zootaxa 1124 on pages 58-60, DOI: 10.5281/zenodo.17178

The roles of kairomones, synomones and pheromones in the chemically-mediated behaviour of male mosquitoes

International audienceDespite decades of intensive study of the chemical ecology of female mosquitoes, relatively little is known about the chemical ecology of males. This short review summarizes the current state of knowledge of the chemicals that mediate male mosquito behaviour. Various trophic interactions including insect–plant, insect–host, and insect–insect responses are emphasized. The relevance of the chemical ecology of male mosquitoes in the context of vector control programmes is discussed

Syntheses, characterizations, and biological activities of tetradeca-4,8-dien-1-yl acetates as sex attractants of leaf-mining moth of the genus Phyllonorycter (Lepidoptera: Gracillariidae)

The four possible isomers of tetradeca-4,8-dien-1-yl acetate and corresponding alcohols were synthesized stereoselectively by synthetic routes employing Wittig coupling reaction for the preparation of (Z,E)- and (Z,Z)-isomers, and alkylation of terminal alkynes for the preparation of (E,E)- and (E,Z)- isomers as the key steps. Synthetic products were characterized by 13C- and 1H-NMR spectroscopy as well as mass-spectrometric methods. All four isomers gave distinctive mass spectra where m/z 81 fragments clearly dominated. Elution order, followed by retention index presented in parenthesis, of tetradeca-4,8- dien-1-ols was determined as (Z,Z) (2082.1), (Z,E) (2082.8), (E,E) (2083.1), and (E,Z) (2083.2) from unpolar SPB-1 column, and as (E,E) (2210.2), (Z,E) (2222.1), (E,Z) (2223.4), and (Z,Z) (2224.7) from polar DB-WAX column. The isomers of tetradeca-4,8-dien-1-yl acetates eluted in the order of (Z,Z) (2176.1), (Z,E) (2178.4), (E,Z) (2185.9), and (E,E) (2186.4) from SPB-1, and (Z,E) (2124.3), (E,E) (2157.7), (Z,Z) (2128.9), and (E,Z) (2135.9) from DB-WAX columns. Field-screening tests for attractiveness of tetradeca-4,8-dien-1-yl acetates revealed that (4Z,8E)-tetradeca-4,8-dien-1-yl acetate significantly attracted Phyllonorycter coryli and Chrysoesthia drurella males. (4E,8E)-Tetradeca-4,8- dien-1-yl acetate was the most efficient attractant for Ph. esperella and Ph. saportella males, and (4E,8Z)- tetradeca-4,8-dien-1-yl acetate was attractive to Ph. cerasicolella malesRoyal Institute of Technology, Stockholm, [email protected] Didžiojo universitetasŠvietimo akademij

Plasmodium metabolite HMBPP stimulates feeding of main mosquito vectors on blood and artificial toxic sources

Recent data show that parasites manipulate the physiology of mosquitoes and human hosts to increase the probability of transmission. Here, we investigate phagostimulant activity of Plasmodium-metabolite, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), in the primary vectors of multiple human diseases, Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Aedes aegypti, and Culex pipiens/Culex torrentium complex species. The addition of 10 µM HMBPP to blood meals significantly increased feeding in all the species investigated. Moreover, HMBPP also exhibited a phagostimulant property in plant-based-artificial-feeding-solution made of beetroot juice adjusted to neutral pH similar to that of blood. The addition of AlbuMAXTM as a lipid/protein source significantly improved the feeding rate of An. gambiae s.l. females providing optimised plant-based-artificial-feeding-solution for delivery toxins to control vector populations. Among natural and synthetic toxins tested, only fipronil sulfone did not reduce feeding. Overall, the toxic-plant-based-artificial-feeding-solution showed potential as an effector in environmentally friendly vector-control strategies