Prelim Bits 05-02-2024 | UPSC Daily Current Affairs

Thrips parvispinus

The recent study states that ‘new invasive species of Thrips Parvispinus in Florida is tiny but deadly to landscapes and crops’.

Thrips are important group of sucking pests which cause significant economic losses both as pests and vectors of serious plant viruses in several horticultural crops.

• Common name – Karny, an invasive pest species.
• Size – The adult female is smaller than a pencil tip but visible to naked eye and their larvae are transparent.
• Life cycle – About 2 weeks, the female is fertile within 9 days, laying about 15 eggs in a clutch. 
• Feed – It is a polyphagous species, infesting beans, eggplant, papaya, chilli, pepper, potato, strawberry, tobacco and also it inflicts injury to ornamentals plants like Chrysanthemum.
• Infestations – Adults mainly colonize on flowers and underside of leaves whereas larvae suck sap from under surface.
• It also scratches the flesh, leading to curling leaves, stippling, scabbing and stunted growth, heavy flower drop and thereby reducing fruit production.
• Spread – They are present in at least 17 countries, including India, Indonesia, Japan, Taiwan, Singapore and Thailand.
• In India – It was 1^st reported on Papaya from Bengaluru in 2015.
• During Rabi season of 2021-22, they were reported in chilli growing areas of Andhra Pradesh, Telangana and Karnataka.
• Its infestation increased during heavy rainfall of North East monsoon in contrast to other thrips species.
• Control measures - Promotion of cultural practices like deep summer ploughing, intercropping, clean cultivation, balanced use of fertilisers, uprooting and destruction of plant debris and Integrated Pest Management (IPM) strategies for pest control.

In India, Thrips Parvispinus might have dominated or even replaced the native chilli thrips known as scirtothrips dorsalis.

References

1. The Palm Beach Post| Taming the new invasive pest in Florida
2. The New Indian Express| Thrips parvispinus attack in India
3. IIHR| Thrips parvispinus

Pink Lake

Senegal’s pink lake is on the verge of disappearing.

• Name – Lake Retba, better known as Lac Rose (the Pink Lake).
• Location – Around 35km from the city of Dakar, Senegal and it sits in a depression with a shoreline 6.5 metres below sea level.
• Water source – While the sea provides most of the lake’s water and all of its salt, it is isolated from the sea by sand dunes and its fresh water comes from the seasonal water table in the dunes, which are higher than the lake.
• Pink colour – Due to Dunaliella salina which contains red pigments.

When salinity is high, algae with red pigments thrive, and when salinity is low, they give way to other algae rich in green pigments.

• Challenges – Today, salt accumulation poses several challenges.

The supply of salt to the lake through the dunes is a permanent phenomenon, amounts to around 360,000 tonnes per year according to the results of our studies in 2008-2009. 

• Drainage channel on the Southern shore introduces soil particles into the lake and dilutes the water quality and salt quality.
• Unfit and uncultivated salts would fill in the depression in few years, and the Pink Lake will disappear altogether.

Water samples from Pink Lake reveal extremely high levels of nitrates as of 2023.The nitrate limit set by the World Health Organization (WHO) is 50 mg/l for water to be considered potable.

• Recommendations to preserve – Prohibit the mining of shell middens and prohibit the exploitation of dune sand.
• Rehabilitate the belt of casuarina trees that stabilise the dunes.
• Ban urbanisation and tourist facilities and promote environmental education and awareness.

Reference

Down To Earth| Pink Lake is under Threat of Extinction

Dusted Apollo

Dusted Apollo was sighted and photographed for 1^st time in Himachal Pradesh at Manimahesh Lake of Chamba.

• It is an extremely rare high altitude butterfly species.
• Scientific name – Parnassius stenosemus.
• Discovery – 1890.
• Size - Medium to large, wingspans ranging from 5 to 7 cm.
• Distribution range – It extends from Ladakh to West Nepal.
• Habitat altitude – It flies between 3,500 to 4,800 meters in the inner Himalayas.
• Threat – Poaching.

Another rare species Regal Apollo (Parnnasius charltonius) was also photographed at Manimahesh Lake in Himachal, which is protected under Schedule II of the Wildlife Protection Act, 1972.

Apollo Species of Butterflies

• They are considered commercially important butterflies and they fetch high prices in the poaching industry.
• In Himachal Pradesh – There are 11 Apollo species recorded, 5 of them are declared as Scheduled species.
• Status – Most of them are now endangered and need immediate attention for their conservation and protection.
• Recommendations – There is a need to promote community awareness about poaching and the importance of these species.
• Also, establishing butterfly parks and conservation reserves in the State should be on the priority list of the government.

Reference

The Hindu| Dusted Apollo Butterflies in Himachal Pradesh.

Seabed Curtain project

Scientists are working on an unusual plan to prevent Antarctic glaciers from melting through seabed curtain project.

• Aim – To build a set of giant underwater curtains in front of ice sheets to protect them from being eroded by warm sea water.
• Need – Ice in Polar Regions is now disappearing at record rates as global warming intensifies.
• Warmer air melts the surface of glaciers, while they are also eroded at their bases by warm seawater.

Loss of the Thwaites and Pine Island glaciers could be enough to raise sea levels round the world by 3 metres if they melted.

• Proposal – To construct a 100km-long curtain attached to the bed of the Amundsen Sea and would rise by about 200 metres.
• Curtain – It would stretch along the seabed opposite the Thwaites and Pine Island glaciers to act as plugs that prevent the giant ice sheets behind them from sliding into the ocean.
• Working – It would partially restrict the inflow of relatively warm water that laps at the bases of coastal Antarctic glaciers and undermines them.

The Seabed Curtain project, if implemented, would be one of the biggest geo-engineering programmes ever undertaken.

Reference

The Guardian| Seabed Curtain Project

Higher photorespiration in warmer climates

A ground-breaking study by a team led by the Pennsylvania State University has revealed that trees release more carbon dioxide (CO2) in warmer and drier climates.

• Trees – They are considered the lungs of our planet Earth.
• Currently, plants absorb around 25% of human-emitted CO2, acting as a crucial carbon sink.

Rate of photorespiration is measured using wood samples. Researchers can now predict future tree "breathing" and unravel the past by examining fossilised wood.

• Findings of the research – It have challenged the prevailing notion of trees as climate change warriors.
• Accelerated photorespiration – In regions with heightened temperatures and water scarcity.
• Rate of photorespiration – It is up to 2 times higher in warmer climates, especially when water is limited than the cooler and wetter regions.

Reducing carbon dioxide emissions is crucial for mitigating climate change, as this is a major greenhouse gas contributing to global warming.

Reference

Wion News| Trees are giving out more CO2 in warmer regions