Parasites are perhaps uniquely predisposed to rapid evolution under global change. Not only are effective population sizes large and generation times typically short, but transmission imposes an exceptionally strong filter to exclude maladaptation: infective stages either find a host or die,Climate change poses a threat to the control of pest and disease invasions. These “pests and diseases” include insects, plant diseases, and invasive weeds. As climate variables continue to change in the Central Valley, new pests and diseases may become able to invade previously uninhabitable areas like Yolo County,Such parasite includes; mosquitos, Tse-tse flies, Grasshopper, Bedbug, scorpion, cochcroch , Tick, Scabies, Crab louse,Bees,ETC
Climate factors that aid in pest and disease invasions are mostly temperature related and include increasing average temperatures, warmer winter minimum temperatures, changes in precipitation patterns, and water shortages
Genotypes better suited to transmission under particular conditions will presumably be strongly selected for, with unpredictable variation in climate or host availability encouraging genetic diversity and within-genotype flexibility in key life-history traits.
The potential for parasites to out-evolve their hosts suggests that increasing, rather than decreasing, parasite risks and burdens will be the norm under global change.
Parasite lifespan, and the time spent inhabiting different hosts, will influence the susceptibility of parasites to environmental changes, and the type of responses that are most likely to arise. Whereas short-lived parasites with rapid life cycles may be more capable of evolving adaptive response to chronic directional changes in environments, long-lived individuals may be better equipped to withstand acute, transient perturbations.
However, the complex interactions of current stressors, as discussed thus far, can also act upon parasites at the genetic level, complicating predictions and leading to unexpected future infection patterns. Observations of parasite evolution in response to changing environments in nature are rare, but results from a few example systems are offered here to illustrate the potential diversity of parasite adaptive responses to global change
Indeed some expert reveals that “Integrated pest management lies at the center of insect, disease, and weed control. The combination of farming strategies, biological control agents, and necessary pesticide and herbicide use has helped some local farmers address pest problems using a variety of methods”.
In conclusion, the spread of pests and disease through human vectors will continue to become a problem, especially as they become more tolerant to environmental conditions.