Phenotypic plasticity in the labral fan of simuliid larvae (Diptera): effect of seston load on primary-ray number

1999 ◽  
Vol 77 (12) ◽  
pp. 1843-1849 ◽  
Author(s):  
Peter Lucas ◽  
Fiona F Hunter
Keyword(s):  
Phenotypic Plasticity ◽  
Species Identification ◽  
Food Supply ◽  
Feedback Mechanism ◽  
Filter Feeding ◽  
Black Fly ◽  
Species Diagnosis ◽  
Feeding Regimes ◽  
Simulium Decorum ◽  
Plastic Trait

The number of primary rays in the labral fan of filter-feeding black fly (Diptera: Simuliidae) larvae has been used by some authors to aid in species identification. We examined the number of primary labral fan rays in field-collected last-instar larvae of Simulium rostratum and Simulium decorum. Significant inter- and intra-specific differences were found both spatially and temporally. Simulium rostratum and S. decorum larvae were also reared to last instar (from eggs or first- or second-instar larvae) under three feeding regimes to test the effect of seston load on the number of primary labral fan rays. In both species the fan-ray number decreased when the food supply was increased. We conclude that the primary fan ray number should be used cautiously in species diagnosis because it is a phenotypically plastic trait that varies with seston load. A potential feedback mechanism to explain the observed differences in fan-ray number is hypothesised.

The role of hormones

2018 ◽  
Author(s):  
H. Frederik Nijhout ◽  
Emily Laub
Keyword(s):  
Phenotypic Plasticity ◽  
Social Behavior ◽  
Parental Care ◽  
Juvenile Hormone ◽  
Reproductive Behavior ◽  
Hormonal Control ◽  
Plastic Trait

Many behaviors of insects are stimulated, modified, or modulated by hormones. The principal hormones involved are the same as the ones that control moulting, metamorphosis, and other aspects of development, principally ecdysone and juvenile hormone. In addition, a small handful of neurosecretory hormones are involved in the control of specific behaviors. Because behavior is a plastic trait, this chapter begins by outlining the biology and hormonal control of phenotypic plasticity in insects, and how the hormonal control of behavior fits in with other aspects of the control of phenotypic plasticity. The rest of the chapter is organized around the diversity of behaviors that are known to be controlled by or affected by hormones. These include eclosion and moulting behavior, the synthesis and release of pheromones, migration, parental care, dominance, reproductive behavior, and social behavior.

ECOLOGY OF BLACK FLIES (DIPTERA: SIMULIIDAE) OF THE SOURIS RIVER, MANITOBA AS A BASIS FOR CONTROL STRATEGY

1981 ◽  
Vol 113 (3) ◽  
pp. 223-234 ◽  
Author(s):  
A. R. Westwood ◽  
R. A. Brust
Keyword(s):  
Control Program ◽  
Abundant Species ◽  
Pest Species ◽  
Black Flies ◽  
Black Fly ◽  
Simulium Vittatum ◽  
Late Instar ◽  
Simulium Decorum ◽  
Fly Control ◽  
Wire Cage

AbstractTen species of black flies were collected from the Souris River, Manitoba between April 1977 and October 1978. Adults of Simulium luggeri Nicholson and Mickel, Simulium meridionale Riley, Simulium venustum Say, Simulium verecundum Stone and Jamnback, and Simulium johannseni johannseni (Hart) were collected feeding on livestock and humans, and are well known pest species. Simulium vittatum Zetterstedt was the most abundant species, but was not a pest on man or domestic animals. Simulium tuberosum (Lundström) and Simulium johannseni duplex Shewell and Fredeen were the least abundant species. Simulium j. johannseni, S. j. duplex, S. venustum, S. verecundum, S. tuberosum, and Cnephia dacotensis (Dyar and Shannon) appeared to be univoltine species while S. luggeri, S. meridionale, Simulium decorum Walker, and S. vittatum were multivoltine in the Souris River.An evaluation of cone, plate, rope, and wire cage sampling devices for black fly larvae and pupae indicated that cone samplers provided a more representative sample for population assessment.In a black fly control program, of the Souris River, Manitoba two separate larvicide treatments in spring may be necessary. In the case of two treatments, the first should be aimed at late instar larvae of S. j. johannseni, S. venustum, and S. verecundum. Since the majority of S. luggeri and S. meridionale would be in the egg stage at this time, a second treatment, 10–14 days later, would be necessary to control late instar larvae of these species.

Reassessing species boundaries in the Syagrus glaucescens complex (Arecaceae) using leaf anatomy

Botany ◽  
2021 ◽  
pp. 379-387
Author(s):  
D.H.T. Firmo ◽  
S.A. Santos ◽  
M.E.M.P. Perez ◽  
P. Soffiatti ◽  
B.F. Sant’Anna-Santos
Keyword(s):  
Species Identification ◽  
Leaf Anatomy ◽  
Vascular System ◽  
Identification Key ◽  
Species Boundaries ◽  
Vascular Bundles ◽  
Geographical Isolation ◽  
Species Occurrence ◽  
Species Diagnosis ◽  
High Degree

The Syagrus glaucescens complex comprises three species: Syagrus glaucescens Glaz. ex Becc., Syagrus duartei Glassman, and Syagrus evansiana Noblick. Recently, a new population of S. evansiana that possesses a high degree of endemism was reported in the Serra do Cabral mountain. Here we intend to study the leaf anatomy of the S. glaucescens complex and confirm whether this newly found population (from now on called Syagrus aff. evansiana) belongs to S. evansiana or not. Specimens were collected to investigate their leaf anatomy, which showed distinct differences between S. aff. evansiana and S. evansiana. The midrib anatomy revealed novelties for the S. glauscecens complex, proving useful for species diagnosis. Features such as accessory vascular bundles around the vascular system of the midrib and the number of collateral bundles are diagnostic for species identification. In addition, morphological and anatomical analyses indicated a correlation with the species occurrence. We found greater similarity between S. glaucescens and S. duartei, while S. evansiana and S. aff. evansiana are more alike. Here, we propose a new identification key based only on the leaf anatomy. Despite their morphological similarities, S. aff. evansiana and S. evansiana presented differences in leaf anatomy, which — when associated with their geographical isolation — suggests a fourth taxon in the complex.

scholarly journals Evaluation of Partially Submerged Sticky Traps On Lake Spillways For Adult Black Fly (Diptera: Simuliidae) Surveillance and Arbovirus Detection

2018 ◽  
Vol 34 (4) ◽  
pp. 306-310
Author(s):  
Michael C. Cavallaro ◽  
Eric Risley ◽  
Paige Lockburner
Keyword(s):  
Adult Female ◽  
Rural Areas ◽  
Surveillance Systems ◽  
Black Flies ◽  
Culex Mosquito ◽  
Sticky Traps ◽  
Black Fly ◽  
Equine Encephalitis Virus ◽  
Simulium Decorum ◽  
Average Standard Error

ABSTRACT Sentinel surveillance systems demonstrate an improved ability to supplement monitoring data and anticipate arbovirus outbreaks (i.e., sentinel avian species). Management complications can arise during unpredictable or unseasonal disease detections, especially in rural areas where resident distribution is patchy. Using spillways near residential lake communities as static surveillance locations, we tested a novel partially submerged sticky trapping technique and screened wild populations of adult female black flies (Diptera: Simuliidae) for West Nile virus (WNV) and eastern equine encephalitis virus (EEEV). Trap site selection criteria considered the density of immature black fly colonization on spillway surfaces and the number of positive detections of arboviral targets in nearby Culex mosquito populations. On average (±standard error), sticky traps captured 134 (±33) adult black flies over a 24-h period, with 1 trap capturing as many as 735 individuals. Although we detected positive cases of WNV from 20 Culex mosquito trapping sites within 16 km (approx. flight radius) of the selected lake spillways, mixed pools of adult female Simulium vittatum complex and Simulium decorum were all negative for both arboviruses. This study yielded an application for partially submerged sticky traps to collect adult female black flies. Its potential uses for monitoring the infection rates of more well-documented Simulium parasites are discussed.

THE INFLUENCE OF FORMULATION ON TOXICITY AND AVAILABILITY OF A PESTICIDE (METHOXYCHLOR) TO BLACK FLY LARVAE (DIPTERA: SIMULIIDAE), SOME NON-TARGET AQUATIC INSECTS AND FISH

1981 ◽  
Vol 113 (4) ◽  
pp. 281-293 ◽  
Author(s):  
R. J. Sebastien ◽  
W. L. Lockhart
Keyword(s):  
Aquatic Insects ◽  
Aquatic Organisms ◽  
Filter Feeding ◽  
Chironomid Larvae ◽  
Black Fly ◽  
Fly Larvae

AbstractTwo formulations of methoxychlor were compared with regard to toxicity and availability to aquatic organisms. A particulate formulation was less toxic than an emulsifiable formulation to chironomid larvae, stonefly nymphs, and fish. Similarly the particulate methoxychlor was less rapidly accumulated from water by those same animals than was the emulsified methoxychlor. With black fly larvae, the only filter-feeding animal used, the two formulations were about equal in toxicity, but the particulate formulation was accumulated more readily than emulsified material. Both formulations induced larvae to detach from substrate but emulsifiable methoxychlor acted more quickly. At the time of detachment, larvae exposed to the particulate formulation contained an average of 68 times more methoxychlor than larvae exposed to the emulsion.

scholarly journals The evolution of neurosensation drives the gain and loss of phenotypic plasticity

2021 ◽  
Author(s):  
Emily Y Chen ◽  
Diane K Adams
Keyword(s):  
Phenotypic Plasticity ◽  
Environmental Change ◽  
Molecular Mechanism ◽  
Pleiotropic Effects ◽  
Species Evolution ◽  
Complex Mechanisms ◽  
Gain And Loss ◽  
Insight Into ◽  
Plastic Trait

Phenotypic plasticity is widely regarded as important for enabling species resilience to environmental change and for species evolution. However, insight into the complex mechanisms by which phenotypic plasticity evolves in nature has been limited by our ability to reconstruct evolutionary histories of plasticity. By using part of the molecular mechanism, we were able to trace the evolution of pre-feeding phenotypic plasticity across the class Echinoidea and identify the origin of plasticity at the base of the regular urchins. The neurosensory foundation for plasticity was ancestral within the echinoids. However, coincident development of the plastic trait and the neurosensory system was not achieved until the regular urchins, likely due to pleiotropic effects and linkages between the two colocalized systems. Plasticity continues to evolve within the urchins with numerous instances of losses associated with loss of sensory capabilities and in one case loss of neurons, consistent with a cost associated with maintaining these capabilities. Thus, evidence was found for the neurosensory system providing opportunities and constraints to the evolution of phenotypic plasticity.

Efficiency of filter feeding of black fly larvae (Diptera: Simuliidae)

1978 ◽  
Vol 56 (7) ◽  
pp. 1608-1623 ◽  
Author(s):  
Daniel C. Kurtak
Keyword(s):  
Laboratory Experiments ◽  
Black Flies ◽  
Natural Conditions ◽  
Filter Feeding ◽  
Black Fly ◽  
The Mean ◽  
Fly Larvae ◽  
Single Larva

Larvae of nine species of black flies were exposed to synthetic particles in the laboratory. Sizes and concentrations of particles were chosen to simulate natural conditions. Smaller particles (diameter 5–10 μm) were offered at a rate of 50–100/cephalic fan area per second, and larger ones (diameter approximately 150 μm) at 0.3–1.0/cephalic fan area per second. Experiments were conducted at water velocities of 30, 50, and 70 cm/s.In all the laboratory experiments, only a small percentage of the particles passing through an area equal to that of the cephalic fans of a single larva were ingested. Particles larger than the spacing between the fan rays were ingested more efficiently than smaller ones. At 50 cm/s, the mean percentage ingested for all species was 1.6% (0.14–8.3%) of particles 150 μm in diameter and 0.094% (0.0026–0.76%) of particles 5–10 μm in diameter. The percentage of material ingested decreased at higher concentrations and water velocities. There were significant differences among the species.Experiments were done with one of the species in the field with similar results.Based on this work, an individual black fly larva in nature probably ingests 1–10% by weight of the material passing through its cephalic fans.

Absence of population structure in black flies as revealed by enzyme electrophoresis

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 531-537 ◽  
Author(s):  
R. M. Feraday ◽  
K. G. Leonhardt
Keyword(s):  
Population Structure ◽  
Allozyme Variation ◽  
Structure Evolution ◽  
Population Subdivision ◽  
Enzyme Electrophoresis ◽  
Black Flies ◽  
Chromosome Inversion ◽  
Black Fly ◽  
Shifting Balance ◽  
Simulium Decorum

Analysis of allozyme variation by the FST-statistic in Simulium decorum and several other black fly species reveals very little genetic variation that could be attributed to genetic drift. This is consistent with what is known about the rates of migration of black flies and supports the idea that there is a lack of population subdivision in these insects. This picture of population structure is quite different from that presented by chromosome inversion polymorphisms. Chromosomal variation, however, can reasonably be attributed to selection and suggests that the role of inversions in black fly evolution is similar to population subdivision in the shifting balance process.Key words: black flies, allozymes, population structure, evolution.

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