Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Citation classic - optimal foraging - a selective review of theory and tests

Mites of Greenhouses, Identification, Biology and Control

Bees. Their Vision, Chemical Senses, and Language

Revue française d'allergologie et d'immunologie clinique

World crop pests (editor-in-chief W. Helle). Volumes 1A and 1B: Spider Mites: Their Biology, Natural Enemies and Control

This review summarizes some of the important reproductive strategies in phytophagous acarine pest, Tetranychus urticae Koch 1836. It is an economically important agricultural pest with a global distribution which feeds on a wide range of host plant species throughout the world. The rapid developmental rate, high reproductive potential, and arrhenotokous parthenogenesis in T. urticae allows them to achieve damaging population levels very quickly when growth conditions are good, resulting in an equally rapid decline of host plant quality. Moreover, webbing, habitat preference on the underside of leaves, ballooning and high dispersal rate provide additional benefit to the expanding populations of two spotted spider mite, T. urticae.

https://www.entomoljournal.com/archives/2014/vol2issue5/PartA/16a.pdf

A review on reproductive strategies in two spotted spider mite, Tetranychus Urticae Koch 1836 (Acari: Tetranychidae)

Managed pollination is an essential input in enhancing the crop productivity. In recent years, there has been an increase in the accumulation of data to indicate that seed yields of insect pollinated crops may often be lower than the expected, not because of adverse climatic, edaphic or cultural factors, but simply because the number of certain pollinators is inadequate. In absence of pollination in many entomophilous crops, fruit or seed set is affected adversely even if all the cultural practices are followed meticulously. Insect pollinators set a greater proportion of early flowers of the crop and increase quality and quantity of the seed yield. Before the use of managed pollination, it is necessary to have a basic knowledge of factors which influence pollinator activity and preference of the pollinators for different crops. This review summarizes the pollination biology of the important vegetable crop, Allium cepa L., commonly known as onion.

The pollination biology of onion (Allium cepa L.)- A Review

Field trials were conducted to assess the damage potential of two-spotted spider mite (Tetranychus urticae Koch) on cucumber (Cucumis sativus Linnaeus). Young cucumber plants were artificially infested with different densities of T. urticae (5, 10, 15 and 20 mites/ grown up leaf) while uninfested plants acted as control. Post infestation, the plants differed in their support to mite density in accordance with initial infestation density and observation period. Grown up leaves were found to be the most susceptible to mite infestation (5.86 mites/ sq. cm leaf). The number of feeding (chlorotic) patches on cucumber leaves significantly increased from 1.38/sq cm at a pre-count of 5 mites per grown up leaf to 1.71/sq cm leaf at a pre-count of 20 mites as compared to no patch recorded in control. Highly significant negative correlation was recorded between mite population and photosynthetic pigments. Total chlorophyll, chlorophyll-a, chlorophyll-b and carotenoids decreased to a maximum of 40, 43.63, 45.45 and 47.27 percent at the highest infestation density as compared to control. Results revealed differences among various treatments in terms of yield attributes of cucumber. The per cent reductions from 6.15 to 12.42 in number of fruits, 0.59 to 1.56 in fruit length and 0.93 to 3.28 in fruit width at different inoculums of T. urticae were recorded over uninfested plants. The cumulative effect led to the ultimate reduction in average fruit weight in the range of 10.16 to 17.19 per cent in the infested plants.

https://journals.ansfoundation.org/index.php/jans/article/download/395/380

Damage potential of Tetranychus urticae Koch to cucumber fruit and foliage: Effect of initial infestation density

Field trials were conducted to evaluate the acaricidal potential of entomopathogenic fungus, Beauveria bassiana and aqueous extracts of Withania somnifera and Glyccirrhyza glabra against the mobile stages of Tetranychus urticae Koch on cucumber. The treatments responded in a concentration dependent manner. Highest reduction in T. urticae population was achieved with Omite (0.05%) followed by Nimbecidine (5ml/l), B. bassiana (10 10 spores ml -1 ), W. somnifera (7.5%), B. bassiana (10 8 spores ml -1 ), G. Glabra (7.5%), G. Glabra (5%), G. Glabra (2.5%), W. somnifera (5%) and W. somnifera (2.5%). Higher yield was recorded in all the treatments as compared to control. In terms of percent increase in yield, Omite caused highest increase (23.65% over control) followed by Nimbecidine, B. bassiana (10 10 spores/ ml), W. somnifera (7.5%), B. bassiana (10 8 spores/ ml), G. Glabra (7.5%), W. somnifera (5%), G. Glabra (5%), G. Glabra (2.5%), and W. somnifera (2.5%) showing 13.97, 11.82, 10.75, 8.67, 8.67, 8.6, 6.76, 6.48 and 6.45 percent increase over control, respectively. These data suggest that the tested biorationals at higher concentrations have the potential to be employed in pest management programs designed for T. urticae control.

https://journals.ansfoundation.org/index.php/jans/article/download/376/360

Kanika Tehri

Papers

A review on reproductive strategies in two spotted spider mite, Tetranychus Urticae Koch 1836 (Acari: Tetranychidae)

The pollination biology of onion (Allium cepa L.)- A Review

Damage potential of Tetranychus urticae Koch to cucumber fruit and foliage: Effect of initial infestation density

Field efficacy of some biorationals against the two spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae)

Determination of lethal concentration and lethal time of entomopathogen Beauveria bassiana (Balsamo) Vuillemin against Tetranychus urticae Koch.