Papers by Mitchell B Baker
Journal of Economic Entomology, 2020
Eastern New York State is frequently the site of Colorado potato beetle (Leptinotarsa decemlineat... more Eastern New York State is frequently the site of Colorado potato beetle (Leptinotarsa decemlineata, Say) populations with the highest observed levels of insecticide resistance to a range of active ingredients. The dominance of a resistant phenotype will affect its rate of increase and the potential for management. On organic farms on Long Island, L. decemlineata evolved high levels of resistance to spinosad in a short period of time and that resistance has spread across the eastern part of the Island. Resistance has also emerged in other parts of the country as well. To clarify the level of dominance or recessiveness of spinosad resistance in different parts of the United States and how resistance differs in separate beetle populations, we sampled in 2010 beetle populations from Maine, Michigan, and Long Island. In addition, a highly resistant Long Island population was assessed in 2012. All populations were hybridized with a laboratory-susceptible strain to determine dominance. Non...
Estimates of recapture probabilities calculated with SURGE.
☯ These authors contributed equally to this work.
Agricultural and Forest Entomology, 2008
1 Resistance to insecticides is a model system for studying adaptation. Although selection for re... more 1 Resistance to insecticides is a model system for studying adaptation. Although selection for resistance is always strong in areas and seasons where populations are exposed to insecticides, costs of resistance, which may only be expressed in the absence of insecticide use, will shape how quickly resistance will evolve.
Oikos, Aug 11, 2008
... Stuart P. Sharp,; Mitchell B. Baker,; Jarrod D. Hadfield,; Michelle Simeoni,; Ben J. Hatchwel... more ... Stuart P. Sharp,; Mitchell B. Baker,; Jarrod D. Hadfield,; Michelle Simeoni,; Ben J. Hatchwell. ... The breeding attempts of all individuals were closely monitored every year; the between-year resighting probability of birds still alive is almost one (McGowan et al. ...
American Journal of Potato Research, Sep 24, 2008
The Colorado potato beetle, Leptinotarsa decemlineata (Say), is widely regarded as the most impor... more The Colorado potato beetle, Leptinotarsa decemlineata (Say), is widely regarded as the most important insect defoliator of potatoes. Its current range covers about 16 million km 2 in North America, Europe, and Asia and continues to expand. This insect has a complicated and diverse life history, which is well-suited to agricultural environments, and makes it a complex and challenging pest to control. Dispersal, closely connected with diapause, feeding, and reproduction, allow the Colorado potato beetle to employ "bet-hedging" reproductive strategies, distributing its offspring in both space (within and between fields) and time (within and between years). The Colorado potato beetle played a large role in creating the modern pesticide industry, with hundreds of chemicals tested against it. High selection pressure, together with natural propensity to adapt to toxic substances, eventually resulted in a large number of insecticide-resistant Colorado potato beetle populations. Since the middle of the last century, the beetle has developed resistance to 52 different compounds belonging to all major insecticide classes. Resistance levels vary greatly among different populations and between beetle life stages, but in some cases can be very high (up to 2,000fold). Known mechanisms of Colorado potato beetle resistance to insecticides include enhanced metabolism involving esterases, carboxylesterases and monooxygenases, and target site insensitivity, as well as reduced insecticide penetration and increased excretion. There is also some evidence of behavioral resistance. Resistance mechanisms are sometimes highly diverse even within a relatively narrow geographical area. Resistance is usually inherited as an incompletely dominant or incompletely recessive trait, with one or several genes involved in its determination. Because of pleiotropic effects of resistant alleles, insecticide-resistant beetles often have reduced relative fitness in the absence of insecticides. Rotating different classes of insecticides and reducing insecticidal pressure on pest populations by provision of temporal and spatial refuges from exposure to toxins have been proposed to delay evolution of resistance. However, insecticide resistance in this insect will likely remain a major challenge to the pest control practitioners. Still limited understanding of beetle biology, its flexible life history, and grower reluctance to adopt some of the resistance management techniques create impediments to successful resistance management. Overcoming these obstacles is not an easy task, but it will be crucial for sustainable potato production. Resumen El escarabajo de Colorado de la papa [(Leptinotarsa decemlineata (Say)] es considerado el insecto
Journal of Economic Entomology, 2007
Reduced fitness among resistant versus susceptible individuals slows resistance evolution and mak... more Reduced fitness among resistant versus susceptible individuals slows resistance evolution and makes it easier to manage. A loss of resistance costs could indicate novel adaptations or mutations contributing to resistance. We measured costs of resistance to imidacloprid in a Massachusetts resistant population compared with a Massachusetts susceptible population in 1999 in terms of fecundity, hatching success, egg development time, and sprint speed. Resistance was additive and seemed to be polygenic with high heritability. The fecundity cost appeared overdominant in 1999, and the hatch rate cost was partly recessive in 1999, but neither was significantly different from dominant or recessive. In 2004, we repeated our measures of resistance costs in Massachusetts in terms of fecundity and hatching success, and we added a new resistant population from Maine. In 2005, we compared development time of Maine resistant and the laboratory susceptible colony eggs. Significant fecundity costs of resistance were found in both population in both 1999 and 2004, and significant egg developmental time costs were found in 1999 and 2005. However, the hatching success costs of resistance were significant in 1999 and not apparent in 2004, suggesting some modification or replacement of the resistance genes in the intervening time.
Ann Entomol Soc Amer, 2005
Colorado potato beetle, Leptinotarsa decemlineata (Say), is the most important insect defoliator ... more Colorado potato beetle, Leptinotarsa decemlineata (Say), is the most important insect defoliator of potatoes and is infamous for its ability to develop insecticide resistance. Sperm precedence is an important consideration in developing resistance management plans. We determined the precedence of sperm from a postdiapause spring mating by using irradiated sterile males. We also investigated whether spring mating (with or without fertilization) affects reproduction of overwintered females. Precedence of sperm from spring matings versus overwintered sperm from fall matings was almost complete. Some fertilization from fall matings did take place in this experiment, but it exceeded 10% in only one of the 22 pairings. Females mated only the previous fall laid fewer eggs than spring-mated females, but spring mating did not seem to improve the hatch rate of deposited eggs. On average, mated females started laying 1.6 d sooner than fall-mated females, but this difference was not signiÞcant. Hatch rate did not change with time. Precedence of spring matings over stored sperm can help compensate for assortative summer mating among resistant individuals due to differences in developmental time between refuges and treated areas.
Animal Behaviour, May 31, 2005
Habitat quality, and the levels of habitat variables that are associated with good habitat, can v... more Habitat quality, and the levels of habitat variables that are associated with good habitat, can vary between years. Therefore, animals that are able to adjust their habitat selectivity should enjoy higher fitness. I examined the use of experience in habitat selection during natal dispersal in Hemilepistus reaumuri, a monogamous, semelparous desert isopod. Young from the previous year emerge in the spring and walk from a few to over one thousand metres before establishing burrows or settling in already established burrows. Isopods were held in outdoor pens for 7-day priming treatments, then moved to new pens and tested for settling 4 days later. Perceived habitat quality was defined as the fraction of isopods settling in each pen during its use in the 7-day priming treatments. Settling was tested as a function of the change in perceived quality isopods experienced. Settling was significantly positively correlated with change in perceived quality, suggesting that experience is used to prime habitat selection during dispersal, and that the effects of experience last at least a few days in desert isopods. Time of year also had a significant positive effect on settling. The effect of change in perceived quality was stronger than the effect of perceived quality in the final pen. If changes in habitat are used to calibrate settling decisions, longer dispersal distances may be needed to allow for habitats to be compared. Use of experience to regulate settling may also affect the population dispersal response to habitat change.
Ecology, Apr 1, 2004
... variability to generate evolutionarily stable rates of emigration from a single patch or betw... more ... variability to generate evolutionarily stable rates of emigration from a single patch or between a pair of patches (Hamilton and May ... The authors thank Hugh Dingle, John Eadie, Michael Henshaw, Nadav Nur, Elizabeth Jakob, Jay Rosenheim, Joel Brown, and an anonymous ...
Refuge crops may have contributed to the continuing effectiveness of transgenic insecticidal cult... more Refuge crops may have contributed to the continuing effectiveness of transgenic insecticidal cultivars, but have not been widely used as part of resistance management for conventional insecticides. Much of the theory used to design refuge requirements was based on a lepidopteran life cycle and populations that are initially very susceptible to the high dose insecticide. In many lepidopteran pests, only the larvae are folivorous, and so selection acts only on the larvae in most models of resistance evolution. This study examines the potential for refuge crops to be effective population and resistance management tools for Colorado potato beetle, Leptinotarsa decemlineata, being treated with conventional insecticides, particularly neonicotinoid insecticides. In this model selection takes place among both larvae and adults, with resistance ratios and other parameters drawn from recent examples of resistance evolution to neonicotinoid insecticides. Resistance to neonicotinoids appears to...
Insecticide resistance offers a contemporary opportunity to observe evolution in action. The prim... more Insecticide resistance offers a contemporary opportunity to observe evolution in action. The primary method proposed for slowing the evolution of resistance is the use of refuge crops, and the primary methods used by potato growers, are rotation of fields, and rotation of treatments within fields. Both refuge crops and crop rotation depend critically on movement (or restriction of movement) for their success. Monitoring of rotated and non-rotated potato fields, Solanum tuberosum L., for 3 growers was conducted in 2008 and 2009 in Long Island, NY for the Colorado potato beetle, Leptinotarsa decemlineata (Say). In 2008 I found that colonists of rotated fields on Long Island NY were more resistant that those continuously planted in potato. I am analyzing the 2009 data now. A second study also conducted in 2008 and 2009 compares flyers and walkers emerging from diapause. In 2008 one overwintering site from one grower was used. In 2009 two overwintering sites and two growers were used. F...
Israel Journal of Zoology
We report the results of three studies, one observational and two manipulative, that examine the ... more We report the results of three studies, one observational and two manipulative, that examine the settling behavior of isopods in response to soil moisture and other cues. In a census of isopod settling patterns in twenty-five 5 × 10 m plots arranged on a 200 m2 grid, isopods settled more densely in plots with more successful old burrows from the previous season, and in plots with more shrubs. Isopod settling was not correlated with soil moisture at 10 and 30 cm depths. In a manipulative experiment carried out over two years, isopods settled more densely in 3 × 3 m outdoor pens that received 20 mm of supplemental water in February than in unwatered plots. In a second experiment, 50 mm of water was added to open plots, and two densities of artificial holes were added as well. Isopods settled more densely in plots with added water, and settled much more densely in plots with artificial holes. Water did not significantly affect isopod survival or offspring weight. Unmanipulated plots wi...
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Papers by Mitchell B Baker