eChapters

Pollination is a vital and key component of ecosystem services which is provided by pollinators. FAO, 2007 reported that 80 per cent of plant species rely for pollination on pollinators, which is dominated by insects. Among the insect pollinators, solitary and social bees dominate both managed and natural ecosystems. No other groups of insects are more beneficial to humans than bees. Many plants have evolved intricate relationships with many insect pollinators and without their presence, majority of plant species would not reproduce and maintain their genetic diversity (Daily et al., 1997). In natural ecosystem, insect pollination plays a pivotal role to maintain and conserve the plant biodiversity. On a global scale, the total annual value of insect pollination services has been estimated at USD 217 billion (Sciencedaily, 2008). United Nations reported that the economics of ecosystems and biodiversity by insect pollination was valued at £134 billion.

The Colony Collapse Disorder (CCD) is not a disease; it is multi-factorial syndrome which causes massive losses of honey bee in the USA and elsewhere. It is recorded that in European honey bee (Apis mellifera). The adult worker bee population of the colony demean through catastrophic effects of CCD. The dwindling of adult worker bees in colonies and the lack of noticeable symptoms leads to the nebulous label of CCD. In this syndrome, dead worker bees cannot be found in the colony and their vicinity of bee hive, and stored food (honey and pollen) are not touched by robbers bees and combs remain as such for several weeks even after the collapse. Some scientists; Aizen and Harder, also reported this disorder is not universal and, in fact, global populations of honey bee (A. mellifera) populations are increasing. In the spring of 2007, beekeepers in the US reported a rare kind of bee colony disease where they die off and numerous colonies left their hives and disappeared without a trace. The plight of honey bee in USA has caused concern and attracted great attention of scientists to delve and provide explanations of this mystery and preventive measures. In US, it is also christened “Honey bee AIDS” by some popular media. Indeed, honey bee colonies can die in many ways and CCD is just one of them. Finally, since both honey bee host and pathogens are genetically diverse, the symptoms and causes of colony losses may well be different in varrious regions.

Pollination is a keystone process in both human managed and natural terrestrial ecosystems. Pollinators are an input of crop cultivation and associated biodiversity, and provide an essential ecosystem service to both natural and agro- ecosystems. In agro-ecosystems, management of pollinators can maximize the pollination and thereby enhance the crop productivity and yield quality. Pollination is the best example of mutualism between plant species and their pollinators which results into intricate relationships between plant and animal - the reduction or loss of either affecting the survival of both.

Approximately 80 per cent of all flowering plant species are dedicated to pollination by animals and mostly by insects. The negative impact of pollinator deficit is strongly felt in reduction of fruit set seed productivity and agricultural biodiversity. The role of pollinators is transfer of pollen from anther to stigma of the same species to ensure reproduction, seed set, fruit set development and multiplication of plants, both in agro ecosystems and natural ecosystems.

Agricultural biodiversity is known as crop genetic resources, although agroecosystems hold a wide diversity of other organisms that contribute toward their productivity and sustainability. Amongst these pollinators play the massive role in crop pollination and thus ensure that fruit or seeds are formed. Over 3 decades ago, the international community began to emphasize on the importance of pollinators. In agro-ecosystems, pollinators are essential for agriculture, horticultural and forage production as well as the production of seed for many root and fiber crops. Pollinators such as bees, birds and bats affect 35 per cent of the world’s crop production, increasing outputs of 87 of the leading food crops worldwide, plus many plant-derived medicines in our pharmacies (Klein et al., 2007). Food security, food diversity, human nutrition and plant diversity all rely strongly on animal pollinators. Pollination is an essential ecosystem service that enables plant reproduction and food production. The pollinators’ abundance and diversity play pivotal role for enhancement of the productivity, quality and maintenance of natural resources of plant biodiversity. The diminution of pollination abundance and their diversity certainly affect productivity, quality and plant biodiversity.

Pollinators are organisms that help to transfer pollen from anther to stigma of the same species for fertilization and thereby produce seeds and fruits. Pollinators belong to diverse groups viz. insects, birds, reptiles, mammals, etc. Insects; bees butterflies, moths, wasps, flies, some types of beetles. Out of insect pollinators, bees are most important pollinator. Insect pollinators are critical to the production of many crops and play pivotal role to maintain the biodiversity. The decline in honeybee and other pollinator populations have more attention of scientific and public concern globally as well as in India. A number of factors have been observed as potential contributors to these declines and no single factor has been identified as the cause. The available science suggests that multiple factors responsible for population depletion and extinction, including loss of habitat and food sources, diseases, viruses, pests, and pesticide exposure. It is also known that certain pesticides can pose an immediate or “acute” threat to the insect pollinators and bees. In order to protect pollinators, the labels of pesticides that pose such risks should specify detailed directions of application to reduce potential exposure.

In agro-ecosystem, many agricultural and horticultural crops are dependent on insects for their pollination; their degree of interdependence varies species to species. Some plant species depend primarily on a single pollinator’s species or genus, whereas some plant species accept diverse pollinators. About to 80 per cent of flowering plants’ pollination determined for pollinators (FA0, 2007) and out of that most of the floras depend on insect pollinators for pollination and pollinators depend on flora for their food. Bees are considered as most important pollinator due to their diversity, credential ability and effective pollinators of many plant species. Most of the crops pollination need was met by wild pollinators living within the farming landscape (Kevan and Phillips, 2001). Therefore, pollinators play paramount role in ecosystem through enhance the crop productivity and conserving biodiversity. On the above service of pollinators is priceless and natural endowment, but the society we live in, always categorized and measured in terms of financial value. In 2005, globally, insect pollination services economic value was estimated to be about €153 billion (Gallai et al., 2009). The United Nations also reported that the economics of ecosystems and biodiversity by insect pollination was valued at £134 billion. The assisted pollination may have to be done when natural pollination is insufficient in order to reduce potential yield loss (Klein et al., 2007).

Pollinators provide an essential ecosystem service, namely pollination, and it is an intricate relationship between plants and animals where reduction or loss of either will affect the survival of both. It has been established that pollinating agents are essential for survival and reproduction of several wild plant species (Kearns et al., 1998). About 80% of the world’s flowering plant species are dedicated to animal pollination, mostly by insects (FA0, 2007). Although more than 750,000 insect pollinators have been described (Grimaldi and Engel, 2005), possibly as many as 30 million more await discovery and formal description (Erwin, 2004). In 2005, globally, pollinators’ pollination services economic value was estimated to be about €153 billion (Gallai et al., 2009). The United Nations also reported that the economics of ecosystems and biodiversity by insect pollination was valued at £134 billion. The depletion of insect pollinators is due to pollinators’ habitat destruction, heavy tillage, monoculture, injudicious use of pesticides and climate change and therefore, there is the need to create awareness on conservation and pollination management. Climate change is highly affected to species interaction as well as ecosystem ecology (van-der-Putten et al., 2004; Sutherst et al., 2007). Plant-pollinator interaction in both wild and cultivated plant species is under threat (Biesmeijer et al., 2006).

Approximately 80 per cent of all flowering plant species are specialized for pollination by animals and mostly by insects. These crops account for 65 per cent of global food production, still leaving as much as 35 per cent depending on pollinating animals (Klein et al., 2007). These food crops include delicious products such as many of our tree fruits (e.g., apples, cherries, mangos, and avocados) and nuts (e.g., almonds, peanuts, macadamia nuts, and cashew nut), squashes, cucumbers, melons, citrus, and berries. In addition, many of oil seed crops benefit from bee pollination, such as mustard, coconut, canola, safflower, and many more.

The honey bee (Apis mellifera) is the most commonly used insect in agricultural crops as managed pollinator in North America and Europe, Japan, China, India and many other parts of the world as well. Farmers in the United States rent more than 2.5 million honey bee colonies every year for fulfillment of pollination deficit but today, the honey bee is threatened by colony collapse disorder (CCD). The demand for honey bees in California almond orchards rapidly increased due to increasing acreage, while on the other side, bee colonies decreased due to CCD, but that occurred during a time when honey bee colonies were not easy to procure and as a result, the cost of renting bees shot up from US$50 per hive in 2003 to US$140 per hive in 2006 (Sumner and Boriss, 2006). The rental charge increased about 3 times within 4 years.

In order for a plant to become diseased, three conditions must be present: (1) a pathogen, (2) a favorable environment and (3) a susceptible host. All the strategies we use to manage plant diseases work to remove or limit one of these factors, thus breaking the plant disease triangle. The key to sustainable plant disease management is to establish an agro- ecological system that is favorable to plant growth and development at the population level and adverse to pathogen evolution and epidemic development based on interactions among plants, pathogens, vectors and environment.

Of late, there has been a growing trend for individuals and companies to “Go Green” or be more environmentally friendly. There has also been a opinion that natural and organic products are healthier or safer. The pest control industry has responded to these changes in our culture and business markets with innovations in products, materials, and methods. Requests for “organic” based services have grown to a point where most pest control providers offer services that use only natural pesticides.

Thank you, Dr Tikoo, for a nice introduction and thanks to ATPBR for inviting me to deliver this WebCon. I would like to start with a small introduction that this particular talk is structured as a general introduction to thrips and thrips-transmitted viruses. There is a bit of interest in everyone with regard to the black thrips which has caused havoc in the last couple of years. The topic has significant importance to plant breeders with regard to the new invasive Western Flower thrips, one of the most dreaded thrips, across the globe and the problems associated with the management of resistance in protected cultivation, and, finally how do we go about with regard to the entire management of the thrips and thrips-transmitted virus problems.

General Aspects About Insects

‘Insects’ are almost ubiquitous. They are found all over the world, in the icy regions of the poles, deserts, forests, mountain peaks, oceans and even in oil wells. They can adopt themselves to any climatic conditions and can live in any habitat where food is available. Insects are mostly small, air-breathing organisms of the animal world. Most of the insects live freely in nature. Many species are wild and harmless to human beings. Many are beneficial because of their role in the ecosystem. Some are a part of the food chains of wild creatures, while others through predation and parasitism hold in check many other species of insects. Insects also play a vital role in pollination. Relatively only a few species are harmful to man and are his chief competitor on earth.

The insect body is made up of multicellular tissues. The body is bilaterally symmetrical and is covered by a hard, chitinous exoskeleton. The chitin at the junction of the segments is thinner and pliable and hence insects can bend their bodies. The exoskeleton is made up of several layers of non-living cells produced from the epidermis. Because of the hard chitin us exoskeleton of the body, the growth of the insect is affected beyond a certain extent. So, to facilitate further growth,, this exoskeleton is cast off a few times and this is known as ‘molting’. The number of moultings in a particular species is more or less constant.

Similar to animals of the higher order, insects also possess all important internal systems of organs necessary for the proper performance of the various vital functions. The most important of the systems are the alimentary or digestive system, the circulatory system, the respiratory system, the reproductive system and the excretory system. The fundamental arrangement of the various organs is more or less similar in all insects and does not exhibit much remarkable variations as seen in the external morphological features. The dorsal blood vessel or heart runs along the median line immediately below the dorsal wall. The digestive system including the alimentary canal and its appendages lie in the middle, below the heart. The nervous chain lies below the alimentary canal and immediately above the ventral wall.

Classification of Living Organisms

The classification of living organisms has passed through several changes and has reached the present stage with the gradual assimilation of more and more knowledge about them. The classification is mainly based on the morphology, anatomy, life style, habits, habitats, metamorphosis and such other characteristics. Though the concept of classification of living organisms was perhaps started by Aristotle between 384 - 322 BC, it was the Swedish Scientist Carl Linnaeus (1788), who presented the classification, which was acceptable to most of the Taxonomists. He propounded the binomial nomenclature of naming each and every organism of animal and plant origin with a genetic and species name. In his classification he was consistent in using Latin names for all the organisms.

Insect collection is a source of recreation for many people and maybe a hobby for those who are interested in studying insects. Methods of collection and preservation of insects are the pre-requisite to studying the insects and their various internal and external organs. After collection, it becomes imperative to keep and preserve the insect specimens intact and safe for a longer time to further study the characters or to develop the insect collection museum. Let‘s have a look and do the different types methods of collection, and devices used for the collection and preservation of insects including immature stages in this practical session.

Collection

 The purposes of insect collection are:

To know the occurrence of a particular insect in a particular locality.

Taxonomic study of insects.

Identification of insects.

To study the bionomics and rearing of insects for various entomological experiments.

To develop the insect repository etc.

The grasshoppers are widely distributed throughout the country and may be seen in abundance during monsoon season. For the generalized morphological description, this insect has been considered as the most suitable representative of class insects because its structural details are not much variable. Apart from this, being larger, it can be studied easily. The generalized insect body is divided into 3 distinct body regions: a head, a thorax and an abdomen. Grouping of body segments into distinct regions is known as Tagmosis and the body regions are called Tagmata.

The Head

The collected insect samples can be inspected in the laboratory after detaching the antenna and putting them under the microscope. They can also be studied through the permanent slides of different types of antennae with the help of microscope.

Antennae are mobile sensory segmented appendages of the head. They articulate with head in front or between the eyes and arise from antennal socket. The size and shape of antennae varies in different insects. They are used for sensory perception which includes motion and orientation, odor, sound, humidity, and a variety of chemical cues. The Sensilla on the antenna acts as tactile, olfaction, carbon dioxide, temperature, wind, humidity, and sound receptors.

Structure of Antenna: Antennae consist of three parts

Mouthparts of insects vary among insects of different groups depending upon their feeding habits. They are mainly of two types viz., Mandibulate (feeding mainly on solid food) and haustellate (feeding mainly on liquid food). Insect mouthparts have become modified in various groups to perform the ingestion of different types of food and by different methods. Indeed the modifications in the mouthparts to ingest almost all kinds of the food material, are one of the factors for the success of the group.

1. Biting and chewing type: e.g. Cockroach & grasshopper.

The typical thoracic leg consists of six parts, basal coxa that articulates with the thorax in the pleural region, small trochanter, femur, tibia, segmented tarsus, and pre-tarsus. The coxa is often divided into two parts, the posterior and the anterior (usually the larger part) being called the meron. The trochanter articulates with the coxa but usually forms an immovable attachment with the femur. The femur and tibia are typically the longest leg segments. The tarsus, which is derived from a single segment, - is usually subdivided into individual tarsomeres. The pretarsus may consist of a single claw, but it is usually composed of a pair of moveable claws and one or more pads or bristles. Legs are usually looked upon as the principal organs of terrestrial locomotion.