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Context:

A significant chunk of the world’s agricultural productivity and nutritional security relies on small insect pollinators.

Details:

More than 75% of food crops, fruits, and flowering plants need bees, wasps, beetles, flies, moths, and butterflies to yield successful harvests.

About the Thai Sacbrood Virus

The Thai Sacbrood Virus (TSBV) primarily targets honeybee larvae, affecting colony growth and reproduction, especially threatening Asiatic honeybees (Apis cerana indica). It is less harmful to Western honeybees, its spread has been facilitated by the movement of bee colonies for commercial purposes.

In 1991-1992, an outbreak wiped out 90% of Asiatic honey bee colonies in South India, and the virus resurfaced in Telangana in 2021, with reports from China and Vietnam.

What is pollination?

It is the act of transferring pollen grains from the male anther of a flower to the female stigma. The goal of every living organism, including plants, is to create offspring for the next generation. One of the ways that plants can produce offspring is by making seeds. Seeds contain the genetic information to produce a new plant.

Importance of Pollinators

Importance of Pollinators	Over 75% of food crops and flowering plants depend on insect pollinators like bees, wasps, and butterflies. Pollinator population declines threaten agricultural productivity and economies worldwide.
Role of Wild Bees and Pathogen Spillover	Wild bees are more efficient pollinators than managed honey bees (Apis mellifera). Pathogen spillover between managed honey bees and wild pollinators threatens their health (e.g., deformed wing virus, black queen virus). Swiss study: Shared habitats increased viral loads in wild pollinators by up to 10 times.
Pollinator Diversity and Habitat Overlap	India has over 700 bee species, including four indigenous honey bee species: Asiatic, giant rock, dwarf honey bee, and stingless bee. Habitat loss forces pollinators to share smaller spaces, increasing disease transmission risks.
Case Study: Thai Sacbrood Virus	Recent reemergence of the virus highlights the vulnerability of native bee populations to diseases. Transmission pathways of the virus remain unknown, posing a research gap.
Migration and Competition for Resources	Managed honey bee migrations disrupt ecosystems and compete with native pollinators. In Maharashtra, diseases linked to introduced honey bees have reduced forest honey production.
Need for Focused Research	Dedicated studies on emerging diseases, like the Thai sacbrood virus, can aid in early detection and prevention. Monitoring and controlling diseases in managed colonies can reduce spillover risks to wild pollinators, safeguarding biodiversity and agricultural productivity.

Rising Threat of Diseases Among Bees

Pathogen Spillover	Decline in bee populations observed in Europe and North America, but limited data on bee populations in wildlife-rich areas like the Indian subcontinent. The Western honey bee (Apis mellifera) can carry diseases affecting both managed and wild bees. Pathogen spillover occurs when diseases spread between managed and wild bees sharing the same area.
Study on Disease Spread	A study by Corina Maurer at ETH Zürich, Switzerland, found wild bees sharing flowers with honey bees had 10 times higher disease levels (e.g., deformed wing virus, black queen virus).
Impact of Habitat Loss	Habitat loss forces bees into smaller areas, increasing disease transmission risks.
Role of Flower Habitats	Habitats with more flowers can lower the risk of disease spread between wild and managed bees.
Expert Warning	Axel Brockmann, a retired professor from Bangalore, warned that disease spread is more likely when wild and honey bees share the same habitat due to habitat loss.

Pathogen Spillover occurs when a pathogen transfers from a domestic or non-native species to a wild species, like the spread of disease from managed honey bees to wild pollinators.

Pathogen Spillback is the reverse, where a pathogen moves back to domesticated species from wild populations, causing further ecological impact, such as wildlife diseases being transmitted back to farm animals

About Indian Bees

Total Bee Species	India is home to over 700 species of bees.
Indigenous Honey Bees	Four species: Asiatic honey bee (Apis cerana indica), giant rock bee (Apis dorsata), dwarf honey bee (Apis florea), and stingless bee (Tetragonula).
Habitat	Found across forests, agricultural landscapes, and urban areas.
Role in Pollination	Important for the pollination of food crops and wild plants, supporting biodiversity and agriculture.

Source:

THE HINDU

PRACTICE QUESTION

Q.Pollinators play an important role in ensuring agricultural productivity and maintaining biodiversity. Discuss the ecological and economic significance of pollinators, highlighting the challenges they face and suggesting measures for their conservation. (250 words)

PATHOGEN SPILLOVER & SPILLBACK