The understanding of malaria vector species in association with their bionomic traits is vital for targeting malaria interventions and measuring effectiveness. Many entomological studies rely on morphological identification of mosquitoes, limiting recognition to visually distinct species/species groups. Anopheles species assignments based on ribosomal DNA ITS2 and mitochondrial DNA COI were compared to morphological identifications from Luangwa and Nyimba districts in Zambia. The comparison of morphological and molecular identifications determined that interpretations of species compositions, insecticide resistance assays, host preference studies, trap efficacy, and Plasmodium infections were incorrect when using morphological identification alone. Morphological identifications recognized eight Anopheles species while 18 distinct sequence groups or species were identified from molecular analyses. Of these 18, seven could not be identified through comparison to published sequences. Twelve of 18 molecularly identified species (including unidentifiable species and species not thought to be vectors) were found by PCR to carry Plasmodium sporozoites - compared to four of eight morphological species. Up to 15% of morphologically identified Anopheles funestus mosquitoes in insecticide resistance tests were found to be other species molecularly. The comprehension of primary and secondary malaria vectors and bionomic characteristics that impact malaria transmission and intervention effectiveness are fundamental in achieving malaria elimination.
Abstract. The success of mosquito-based malaria control is dependent upon susceptible bionomic traits in local malaria vectors. It is crucial to have accurate and reliable methods to determine mosquito species composition in areas subject to malaria. An unexpectedly diverse set of Anopheles species was collected in the western Kenyan highlands, including unidentified and potentially new species carrying the malaria parasite Plasmodium falciparum. This study identified 2,340 anopheline specimens using both ribosomal DNA internal transcribed spacer region 2 and mitochondrial DNA cytochrome oxidase subunit 1 loci. Seventeen distinct sequence groups were identified. Of these, only eight could be molecularly identified through comparison to published and voucher sequences. Of the unidentified species, four were found to carry P. falciparum by circumsporozoite enzyme-linked immunosorbent assay and polymerase chain reaction, the most abundant of which had infection rates comparable to a primary vector in the area, Anopheles funestus. High-quality adult specimens of these unidentified species could not be matched to museum voucher specimens or conclusively identified using multiple keys, suggesting that they may have not been previously described. These unidentified vectors were captured outdoors. Diverse and unknown species have been incriminated in malaria transmission in the western Kenya highlands using molecular identification of unusual morphological variants of field specimens. This study demonstrates the value of using molecular methods to compliment vector identifications and highlights the need for accurate characterization of mosquito species and their associated behaviors for effective malaria control.
Phylogenetic relationships among major lineages of the leafhopper subfamily Iassinae were explored by analysing a dataset of 91 discrete morphological characters and DNA sequence data from nuclear 28S rDNA and histone H3 genes and mitochondrial 12S rDNA. Bayesian, maximum-likelihood and maximum parsimony analyses yielded similar tree topologies that were well resolved with strong branch support except at the base of the tree, resulting in equivocal support for inclusion of Bythoniini as a tribe of Iassinae but strong support for the monophyly of Iassinae (excluding Bythoniini) and most previously recognized iassine tribes. Divergence times for recovered nodes were estimated using a Bayesian relaxed clock method with two fossil calibration points. The results suggest that the deepest divergences coincided with Gondwanan vicariant events but that more recent divergences resulted from long-range dispersal and colonization. Biogeographical analyses suggest that the group most likely has a Neotropical origin. The following changes to the taxonomic classification are proposed: establishment of three new tribes, Batracomorphini trib.n. (based on type genus Batracomorphus Lewis), Hoplojassini trib.n. (based on type genus Hoplojassus Dietrich and including one other South American genus), Lipokrisnini trib.n. (based on type genus Lipokrisna Freytag and including two other endemic Caribbean genera); Krisnini is redefined to include only the Old World genera Krisna and Gessius; Iassini is redefined to include only the type genus and four endemic Afrotropical genera; Bascarrhinus Fowler and Platyhynna Berg, recently treated as genera incertae sedis, are placed in Hyalojassini; Thalattoscopus Kirkaldy is added to the previously monobasic tribe Trocnadini. Iassinae now includes 12 tribes, all of which appear to be monophyletic. Revised morphological diagnoses of the subfamily and each of the included tribes are provided and a key to tribes is also given. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid: zoobank.
The wheat stem sawfly, (Cephus cinctus Norton) Hymenoptera: Cephidae, has been a major pest of winter wheat and barley in the northern Great Plains for more than 100 years. The insect’s cryptic nature and lack of safe chemical control options make the wheat stem sawfly (WSS) difficult to manage; thus, biological control offers the best hope for sustainable management of WSS. Entomopathogenic nematodes (EPNs) have been used successfully against other above-ground insect pests, and adding adjuvants to sprays containing EPNs has been shown to improve their effectiveness. We tested the hypothesis that adding chemical adjuvants to sprays containing EPNs will increase the ability of EPNs to enter wheat stems and kill diapausing WSS larvae. This is the first study to test the ability of EPNs to infect the WSS, C. cinctus, and test EPNs combined with adjuvants against C. cinctus in both the laboratory and the field. Infection assays showed that three different species of EPNs caused 60–100% mortality to WSS larvae. Adding Penterra, Silwet L-77, Sunspray 11N, or Syl-Tac to solutions containing EPNs resulted in higher WSS mortality than solutions made with water alone. Field tests showed that sprays containing S. feltiae added to 0.1% Penterra increased WSS mortality up to 29.1%. These results indicate a novel control method for WSS, and represent a significant advancement in the biological control of this persistent insect pest.
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