Millennial-scale paleoenvironmental changes in the central Mediterranean during the last interglacial: Comparison with European and North Atlantic records

The environment of the central Mediterranean Sea is investigated on the basis of high-resolution planktonic foraminifera and calcareous nannofossil data (mean sampling resolutions of about 80 and 160 yr, respectively). MIS 5 is characterized by warm, oligotrophic and stratified waters, while coccolithophore communities developed a vertical zonation that, in today's oceans, is typical of the low-latitude gyres. The temperate-subtropical configuration of planktonic foraminifera and calcareous nannofossil assemblages is repeatedly transformed into a temperate-subpolar one during the suborbital cooling episodes C25-C18. A comparison with European pollen sequences and North Atlantic cores over the interval between about 128 and 110 kyr BP is carried out. Records from this broad geographical area show a series of environmental changes that occurred at comparable times. However, the first cooling episodes were more severe at high-latitude (approximately north of 50°N), where an anticipated end of interglacial conditions can be ascribed. Variations in the rate of the Atlantic meridional overturning circulation and the strength of atmospheric circulation in the Northern Hemisphere are discussed as likely climatic forcing mechanisms.     

Integrated quantitative biostratigraphy of the latest Tortonian-early Messinian Pissouri section (Cyprus): An evaluation of calcareous plankton bioevents

A quantitative study was performed on planktonic foraminifera and calcareous nannofossils of the astronomically dated Late Miocene Pissouri section (Cyprus). Our results confirm the reliability of well-known planktonic foraminiferal events as Catapsydraxparvulus LO (Last Occurrence), sinistral coiling change of Globorotaliascitula, Globorotaliamiotumida group FRO (First Regular Occurrence), Globorotalianicolae FO (First occurrence) and LO, sinistral coiling change of Neogloboquadrinaacostaensis and also of several important calcareous nannofossil events (Amaurolithusprimus FO, Amaurolithusdelicatus FO, Reticulofenestrarotaria FO and FCO). Integrated planktonic foraminifera and calcareous nannoplankton data contribute to an enhanced time resolution of the Tortonian - early Messinian interval in the Levantine basin, and contribute to detailed correlations throughout the Eastern Mediterranean. In addition, we compare methodologies commonly used in calcareous plankton biostratigraphy, and shortly outline sources of bias that can influence the results of stratigraphic studies.     

Sedimentary response to basin inversion: Mid cretaceous-early tertiary pre- to syndeformational deposition at the Areif El Naqa anticline (Sinai, Egypt)

Summary The Areif El Naqa domal anticline in northeastern Sinai is part of the ‘Syrian Arc’ which represents an intraplate orogen that has been formed since the late Cretaceous by inversion of an older half-gaben system as a consequence of the collision of the African and Eurasian plates. The here studied pre- and syn-deformational Upper Albian to Lower Eocene sedimentary succession in the anticline was formed under shallow marine to hemipelagic conditions resulting in predominantly carbonate lithologies with only subordinate siliciclastic intercalations. The depositional history at Areif El Naqa has been reconstructed in terms of sequence stratigraphy on the basis of detailed sedimentological, biostratigraphical, and paleoecological investigations of ten sections including comparisons with age-equivalent successions further north and south as well as published data. Following a late Triassic-early Cretaceous extensional period, tectonically rather quiet conditions prevailed during deposition of the Albian-Turonian successions. Inversion started around the Coniacian. Three main phases of uplift have been determined for the Areif El Naqa anticline on the basis of evidence from lateral facies and thickness changes, local development of pronounced hiatuses, and in comparison to the sequence stratigraphic development in the tectonically quiet region of central east Sinai. The first major compressional phase is interpreted to have taken place in Coniacian-early Santonian times. It is characterized by pronounced facies and thickness changes which were documented in an earlier study byBartov et al. (1980). Nevertheless, inter-regional sea level changes still controlled deposition at Areif El Naqa during this period. The second pulse of tectonic uplift is indicated for the late Campanian-early Maastrichtian. This is based on siliciclastic deposits which are interpreted as having been reworked from older siliciclastic rocks uplifted in the anticlinal core. The third compressional pulse is inferred to be of middle Paleocene to early Eocene age as evidenced by a major hiatus in sections on the northern anticlinal flank. The uplift history at Areif El Naqa has been compared with the tectonic development in other parts of the Syrian Arc and in general seems to reflect major movements which occurred throughout the anticlines of the fold belt.     

The regional record of Albian oceanic anoxic events at the Apulian Platform Margin (Gargano Promontory, southern Italy)

The Gargano Promontory, located on the eastern margin of the Apulia Platform, represents a distinctive Tethyan area where the transition from carbonate platform to adjacent basin is exposed on land. The Albian stratigraphic record, represented by shallow-water, slope and deep-water deposits, provides a good opportunity to investigate the regional response to oceanic anoxic events (OAEs) in different depositional settings by using an integrated, high-resolution micropalaeontological (planktonic foraminifers and calcareous nannofossils) approach. Results show that organic matter preservation is confined to the more distal areas (Marne a Fucoidi Formation), and consists of black shale intervals from the middle and late Albian (Ticinella primula/Prediscosphaera columnata Zones; upper Ticinella praeticinensis Subzone/R. achlyostaurion Zone, respectively). Integrated biostratigraphic data correlate the intervals of black shale deposition to the Urbino and Amadeus levels, previously identified and named in the Umbria-Marche Basin. These black shales record the effects of OAEs 1b and 1c. The biotic changes in the pelagic Albian succession of the Apulian Platform Margin provide evidence for episodes of eutrophication that correlate to the deposition of these black shales. Genetic models for the two episodes of organic matter preservation are proposed, taking into account both global and local controlling factors.     

Calcareous and siliceous phytoplankton stratigraphy of Neogene marine sediments in central Crete (Greece)

Fine laminated diatomaceous beds in outcrops of the Finikia unit (Estavromenos and Athanatoi sections) in the northern part of the Heraklion district in Crete, have yielded a total of 55 marine diatom and 24 silicoflagellate taxa. The diatom assemblages, characterized by species of low latitudes, belong to the upper part of the Nitzschia jouseae biozone (early-late Pliocene). The silicoflagellate associations belong to the local Dictyocha fibula ausonia and Dictyocha hellenica subzones. These subzones correspond to the subzones CN11b (Discoaster asymmetricus) and CN12a (D. tamalis) of calcareous nannofossils respectively, as well as to the Globorotalia puncticulata/G. bononiensis biozones of planktic foraminifera. The sparse silicoflagellate association from fine sandy marls of the Panassos section in the central part of the Heraklion district (Aghia Varvara unit, upper Tortonian-Messinian) is assigned to the local biozone Distephanus speculum minutus. The latter corresponds approximately to the biozone C9 (Discoaster quinqueramus) of calcareous nannofossils and to the Globorotalia conomiozea zone of planktic foraminifera. No discoidal diatoms could be found in the samples from Panassos-section. The presence of silicoflagellates but simultaneous absence of diatoms is probably due to greater opal dissolution within the fine sandy marls of the Panassos section.     

First radiation of Cretaceous planktonic foraminifera with radially elongate chambers at Angles (Southeastern France) and biostratigraphic implications

The study of planktonic foraminifera from the Lower Cretaceous succession at Angles (Southeastern France) directly correlated with ammonites, confirms that the origin of morphotypes with radially elongated chambers occur earlier than previously recorded. In particular, the species Hedbergella semielongata and Hedbergella roblesae bearing subclavate to clavate chambers first appear in the upper Hauterivian, just predating the onset of the oceanic anoxic Faraoni event. Based on these observations, a new zonation is proposed.     

Foraminiferal biofacies and paleoenvironmental implications of the Early Tortonian deposits of Gavdos Island (Eastern Mediterranean)

In this paper two adjacent (Bo and Potamos) sections from the Early Tortonian of the island of Gavdos, Eastern Mediterranean, are extensively studied and compared as for their lithology and micropaleontological content with final aim their paleoecological and paleoenvironmental interpretation. These two sections are composed of clayey sediments and reefal limestones and of marls and sands of turbiditic origin, respectively. The qualitative and quantitative micropaleontological analyses that were realised in the contained benthic microfauna showed that the two sections are characterized by a shallowing upwards-general trend. However, the combined lithological and micropaleontological data suggest that, although adjacent, the two sections underwent different paleoenvironmental evolutions during the early Late Miocene: on the one hand, reef growth at the Bo shelf is suggestive of a current, providing warm, clear and low-nutrient waters to the shelf, and on the other hand, benthic foraminiferal assemblages from the Potamos shelf indicate cooler and eutrophic conditions, induced by enhanced river runoff and upwelling, impeding reefal promotion. This difference may be due to the separation of Bo and Potamos shelf by an island acting as a local oceanographic and biogeographic barrier.     

The marine paleogene of the tremp region (NE Spain)-depositional sequences,facies history,biostratigraphy and controlling factors

Summary The marine Paleogene of the Tremp Basin in the Central Southern Pyrenees corresponds to four depositional sequences which are related to global eustatic third order cycles (Tejas A 2.3–2.6). Associated transgressive and downlap surfaces coincide with boundaries of biozones. Lowstand systems tracts consist of estuarine and braid delta systems. Transgressive and highstand systems tracts are composed of carbonate banks and reefs. Slow thrust-induced changes of the basin topography conditioned the basic type and the areal distribution of carbonate highstand and clastic lowstand systems. Rapid relative sea level changes controlled the activity and internal dynamic of the depositional systems. E-W directed blind thrust anticlines are covered during highstand periods by carbonate fringing banks withNummulites bars. N-S orientation of thrust anticlines leads to the evolution of reef-dominated barrier banks and shelf lagoonal homoclinal ramps. On-bank transport of carbonate sands dominates during transgressions, off-bank transport during highstand periods. Continuous thrusting during the Ilerdian caused angular unconformities only in combination with relative sea level fall. Sequence-internal onlap configurations result from contemporaneous tectonic tilting. Fourth order carbonate bank margin cycles contain well developed lowstand tracts due to increased subsidence rates. Fourth order flooding surfaces are marked by paleosoil horizons at their landward continuation.     

Dietary reconstruction of the Amphipithecidae (Primates, Anthropoidea) from the Paleogene of South Asia and paleoecological implications

The primate family, Amphipithecidae, lived during the early Cenozoic in South Asia. In this study, the diet of late middle Eocene amphipithecids from the Pondaung Formation (Central Myanmar) is characterized using three different approaches: body mass estimation, shearing quotient quantification and dental microwear analysis. Our results are compared with other Paleogene amphipithecids from Thailand and Pakistan, and to the other members of the primate community from the Pondaung Formation. Our results indicate a majority of frugivores within this primate community. Pondaungia and “Amphipithecus” included hard objects, such as seeds and nuts, in their diet. Folivory is secondary for these taxa. Myanmarpithecus probably had a mixed diet based on fruit and leaves. Contrasting results and a unique dental morphology distinguish Ganlea from other amphipithecids. These render interpretation difficult but nevertheless indicate a diet tending towards leaves and fruit. However, the anterior dentition of Ganlea suggests that this taxon engaged in seed predation, using its protruding canine as a tool to husk hard fruits and obtain the soft seeds inside. Bahinia and Paukkaungia, two other Pondaung primates, are small (<500 g) and therefore would have depended on insects as their source of protein. As such, they occupied a very different ecological niche from Pondaung amphipithecids. This primate community is then compared with the Eocene-Oligocene primate communities of the Fayum from North Africa. Similarities between the late middle Eocene Pondaung primate community and extant equatorial and tropical South American primate communities are noted.     

A new pipoid frog (Anura,Pipimorpha) from the Paleogene of Patagonia. Paleobiogeographical implications

The aim of the present contribution is to describe a new genus and species of Pipoidea from the Huitrera Formation (Eocene) from Patagonia, Argentina. The new genus shows a unique combination of characters indicating that it is a valid taxon different from other pipimorphs, including the coeval Llankibatrachus truebae. The phylogenetic analysis resulted in the nesting of the new taxon within a previously unrecognized endemic clade of South American aglossans. This new clade turns out to be the sister-group of crown-group Pipidae. This phylogenetic proposal reinforces the hypothesis sustaining the dispersal of pipids between Africa and South America through an island chain or a continental bridge across the Atlantic Ocean by Early Tertiary times.     

Size variations of the calcareous nannofossil taxon Discoaster multiradiatus (Incertae sedis) across the Paleocene–Eocene thermal maximum in ocean drilling program holes 690B and 1209B

Size measurements of the calcareous nannofossil taxon Discoaster multiradiatus were carried out across the Paleocene–Eocene Thermal Maximum (PETM) in Ocean Drilling Program Holes 690B (Maud Rise, Weddell Sea) and 1209B (Shatsky Rise, Pacific Ocean). Morphometric investigations show that D. multiradiatus specimens are generally larger at ODP Site 1209 than at ODP Site 690. A limited increase in size of D. multiradiatus is recorded at ODP Site 1209, whereas significant enlargements characterize ODP Site 690. Preservation is comparable at both sites: nannofossils are moderately preserved with some evidence of etching/overgrowth in the PETM interval. Yet, D. multiradiatus variations do not correlate with preservation state and morphometric data most likely represent primary signals rather than diagenetic artifacts. There is a direct relationship between D. multiradiatus size and paleotemperatures: largest specimens are coeval with global warming associated with the PETM, inferred to result from excess atmospheric CO₂ due to (partial) oxidation of massive quantities of methane. Size increases and largest specimens of D. multiradiatus occur at different stratigraphic levels within PETM at ODP Sites 690 and 1209. A marked shift in diameter size was observed at the onset and peak of the Carbon Isotopic Excursion (CIE) at ODP Site 690, but only at the end of CIE and initial recovery interval at ODP Site 1209. This diachroneity is puzzling, but indeed correlates well with reconstructed changes in surface and thermocline water masses temperature and salinity in the PETM interval at low and high latitudes. The presumed high concentrations of carbon dioxide seem to have not influenced the morphometry of D. multiradiatus. The major size increase of D. multiradiatus in the CIE of ODP Site 690 could represent the migration of larger-sized allochtonus specimens that moved from peri-equatorial/subtropical areas to higher latitudes during the warmest interval of the PETM, although no direct evidence of distinct populations/subpopulations has been obtained from the frequency diagrams. As a result, we infer that D. multiradiatus is a proxy of water masses stratification and might be used for deriving temperature–salinity–nutrient conditions in the mixed layer and thermocline and their dynamics.     

Distribution of living planktonic foraminifera in the Ross Sea and the Pacific sector of the Southern Ocean (Antarctica)

In order to determine the factors controlling the distribution of planktonic foraminifera as a proxy for reconstruction of paleoenvironments, we present data on live assemblages collected in the Southern Ocean. Plankton tows and hydrographic measurements were taken in the upper 400 m of the water column at different sites in the Ross Sea (site B) and at the Polar Front of the Pacific Ocean (site O) during austral summers from 1998 to 2003.Based on qualitative micropaleontological observations we discriminated between Neogloboquadrina pachyderma dextral (dex) and N. pachyderma sinistral (sin). In addition for N. pachyderma (sin) we distinguished four morphs: the first one (1) has a thickened test and depressed sutures; the second morph (2) is represented by specimens characterized by a subspheric and heavily encrusted test; the third morph (3) has a thin and lobate walled test; the fourth one (4) represent the juvenile stage of N. pachyderma (sin) and is characterized by a smaller average size.The microfauna collected in the Ross Sea (site B) is characterized by the dominance of N. pachyderma (sin) (morphs 1 and 2), whereas low occurrences of Turborotalia quinqueloba, N. pachyderma (dex) and Neogloboquadrina dutertrei were noted in the first 50 m of the water column. The water column at this station is characterized by a marked and shallow stratification and a marked thermocline during the sampling season.At the ocean station (site O), the assemblage shows increasing diversification: T. quinqueloba, G. bulloides, N. pachyderma (dex) and few specimens of Globigerinita uvula characterize the planktonic microfauna. There is a predominance of non-encrusted morphs and juvenile specimens (3 and 4). At this station the mixed surface layer is deeper than in the Ross Sea (60–70 m), the pycnocline and the thermocline less marked.The depth and the intensity of the Deep Chlorophyll Maximum (DCM) influence foraminiferal distribution: N. pachyderma (sin) shows abundance peaks at or just below the DCM while G. bulloides peaks above the DCM. Coiling direction of N. pachyderma seems to be not controlled exclusively by Sea Surface Temperature (SST): probably the two coiling types are genetically different.Results document that diversity of planktonic foraminifera, number of specimens and variations in test morphology are related to regional differences in water properties (temperature, salinity, and DCM depth).     

Evaluating contemporary pollen dispersal in two common grassland species Ranunculus bulbosus L. (Ranunculaceae) and Trifolium montanum L. (Fabaceae) using an experimental approach

Pollen flow is a key biological process that connects plant populations, preventing genetic impoverishment and inbreeding. Pollen‐mediated long‐distance dispersal (LDD) events are especially important for plant species in increasingly fragmented landscapes. Patterns of pollen dispersal were directly estimated and dispersal kernels modelled in an experimental population of Ranunculus bulbosus and Trifolium montanum to determine the potential for LDD. Eight and 11 microsatellite markers were used for R. bulbosus and T. montanum, respectively, to run a likelihood‐based paternity analysis on randomly chosen offspring (N_total = 180 per species) from five maternal plants. High rates of selfing were found in R. bulbosus (average 45.7%), while no selfing was observed in T. montanum. The majority (60%) of mating events occurred at very short distances: the median of the observed dispersal distances was 0.8 m in both species, and the average distances were 15.9 and 10.3 m in R. bulbosus and T. montanum, respectively. Modelling the pollen dispersal kernel with four different distribution functions (exponential‐power, geometric, 2Dt and Weibull) indicated that the best fit for both species was given by a Weibull function. Yet, the tail of the T. montanum pollen dispersal kernel was thinner than in R. bulbosus, suggesting that the probability for LDD is higher in the latter species. Even though the majority of pollen dispersal occurred across short distances, the detection of several mating events up to 362 m (R. bulbosus) and 324 m (T. montanum) suggests that pollen flow may be sufficient to ensure population connectivity in these herb species across fragmented grasslands in Swiss agricultural landscapes.     

The complete mitochondrial genome of the Sichuan taimen (Hucho bleekeri): repetitive sequences in the control region and phylogenetic implications for Salmonidae

The complete mitochondrial DNA genome of the Sichuan taimen (Hucho bleekeri) was determined by the long and accurate polymerase chain reaction (LA-PCR) and primer walking sequence method. The entire mitochondrial genome of this species is 16,997 bp in length, making it the longest among the completely sequenced Salmonidae mitochondrial genomes. It consists of two ribosomal RNA (rRNA) genes, 13 protein-coding genes, 22 transfer RNA (tRNA) genes, and one control region (CR). The gene arrangement, nucleotide composition, and codon usage pattern of the mitochondrial genome are similar to those of other teleosts. A T-type mononucleotide microsatellite and an 82 bp tandem repeat were identified in the control region, which were almost identical among the three H. bleekeri individuals examined. Both phylogenetic analyses based on 12 concatenated protein-coding genes of the heavy strand and on just the control region show that H. bleekeri is a basal species in Salmoninae. In addition, Salmo, Salvelinus and Oncorhynchus all represent monophyletic groups, respectively. All freshwater species occupied basal phylogenetic positions, and also possessed various tandem repeats in their mitochondrial control regions. These results support established phylogenetic relationships among genera in Salmonidae based on morphological and molecular analyses, and are consistent with the hypothesis that Salmonidae evolved from freshwater species.     

Peptide substrates for chymosin (rennin). Interaction sites in kappa-casein-related sequences located outside the (103-108)-hexapeptide region that fits into the enzyme''s active-site cleft.

The role of individual amino acid residues in the 98-102 and 111-112 regions of bovine kappa-casein in its interaction with the milk-clotting enzyme chymosin (rennin) was investigated. to this end the tryptic 98-112 fragment of kappa-casein was modified in its N- and/or C-terminal part by chemical (guanidation, ethoxyformylation, repeated Edman degradation) and enzymic (carboxypeptidase) treatments. Further, use was made of short synthetic kappa-casein analogues in which His-102 had been replaced by Pro or Lys. All peptides and their derivatives were tested comparatively at various pH values for their ability to act as chymosin substrates via specific cleavage of the peptide bond at position 105-106. The results indicate that in the alternating 98-102 sequence (His-Pro-His-Pro-His) the His as well as the Pro residues contribute to the substrate activity with no predominant role of any one of these groups. Another interaction site is formed by the Lys residue at position 111 of the substrate. A model of the enzyme-substrate complex is proposed. Herein the 103-108 fragment of the substrate, to be accommodated within the enzyme's active-site cleft, is brought into position by electrostatic binding (via His-98, His-100, His-102 and Lys-111) near the entrance of the cleft. These interactions are strongly supported by Pro residues at positions 99, 101, 109 and 110 of the substrate, which act as stabilizers of the proper conformation of the substrate in the enzyme-substrate complex.     

(dC-dA)n.(dG-dT)n sequences have evolutionarily conserved chromosomal locations in Drosophila with implications for roles in chromosome structure and function.

In situ hybridization of (dC-dA)n.(dG-dT)n to the polytene chromosomes of Drosophila melanogaster reveals a clearly non-random distribution of chromosomal sites for this sequence. Sites are distributed over most euchromatic regions but the density of sites along the X chromosome is significantly higher than the density over the autosomes. All autosomes show approximately equal levels of hybridization except chromosome 4 which has no detectable stretches of (dC-dA)n.(dG-dT)n. Another striking feature is the lack of hybridization of the beta-heterochromatin of the chromocenter. The specific sites are conserved between different strains of D. melanogaster. The same overall chromosomal pattern of hybridization is seen for the other Drosophila species studied, including D. simulans, a sibling species with a much lower content of middle repetitive DNA, and D. virilis, a distantly related species. The evolutionary conservation of the distribution of (dC-dA)n.(dG-dT)n suggests that these sequences are of functional importance. The distribution patterns seen for D. pseudoobscura and D. miranda raise interesting speculations about function. In these species a chromosome equivalent to an autosomal arm of D. melanogaster has been translocated onto the X chromosome and acquired dosage compensation. In each species the new arm of the X also has a higher density of (dC-dA)n.(dG-dT)n similar to that seen on other X chromosomes. In addition to correlations with dosage compensation, the depletion of (dC-dA)n.(dG-dT)n in beta-heterochromatin and chromosome 4 may also be related to the fact that these regions do not normally undergo meiotic recombination.     

Host-parasite relationships: occurrence and effect of the parasitic isopod Mothocya epimerica on sand smelt Atherina boyeri in the Mesolongi and Etolikon Lagoons (W. Greece)

The parasite-host relationship between Mothocya epimerica, Costa 1851 (Isopoda: Flabellifera: Cymothoidae) and sand smelt Atherina boyeri (Osteichthyes: Atherinidae) fish populations were studied in the Mesolongi and Etolikon Lagoons (W. Greece). Prevalence varied during the year from 12.5% in November to 52.5% in September; overall mean prevalence was 41.9%. Parasite size increased with host size. Infections did not have a significant effect on the host's body condition, such as length-weight relationship, gonadosomatic index, hepatosomatic index and relative condition factor. Histological damage to the host was observed on the gills (especially in the second and third and arches upon which the female parasite rests her abdomen). The physiological cost resulting from this infection seems to be little and probably does not constitute a serious threat for individual host survival.     

Evolution of mitochondrial and ribosomal gene sequences in anophelinae (Diptera: Culicidae): implications for phylogeny reconstruction

In this study, two mitochondrial genes, cyt b and ND5, and the D2 expansion segment of the 28S nuclear ribosomal gene were used to reconstruct a phylogeny of the mosquito subfamily Anophelinae. The ingroup consisted of all three genera of Anophelinae and five of six subgenera of Anopheles. Six genera of Culicinae were used as the outgroup. Extreme conservation at the protein level coupled with rapid saturation of synonymous positions probably accounted for the lack of meaningful phylogenetic signal in the cyt b gene. In contrast, abundant variation at all codon positions of the ND5 gene allowed recovery of the basal and most of the recent relationships. Phylogenetic analysis of D2 produced results consistent with those of ND5. Combined analysis indicated well-supported monophyletic Anophelinae (with Chagasia basal), Anopheles + Bironella, and subgeneric clades within the genus Anopheles. Moreover, subgenera Nyssorhynchus and Kerteszia were supported as a monophyletic lineage. The Kishino-Hasegawa test could not reject the monophyly of Anopheles, whereas the recently proposed hypothesis of close affinity of Bironella to the subgenus Anopheles was rejected by the analyses of ND5 and combined data sets. The lack of resolution of Bironella and Anopheles clades, or basal relationships among subgeneric clades within Anopheles, suggests their rapid diversification. Recovery of relationships consistent with morphology and previous molecular studies provides evidence of substantial phylogenetic signal in D2 and ND5 genes at levels of divergence from closely related species to subfamily in mosquitoes.