ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Sublethal dichlorvos exposure induces cytogenetic damage in Apis mellifera hemocytes

Sadia Maalik, Mehar-un-Nisa Butt, Sajida Mushtaq, Ayesha Hafeez, Naheed Bano, Tauseef Anwar, Huma Qureshi, Salohiddinjon Yunusov, Shuqurillo Ziyadov, Muydinjon M. Muminov, Khudiyev Orkhan, Maksudkhon Sarimsakov, Ibtisam M. Alsudays, Khalid H. Alamer, and Asqar Quvatov

Department of Zoology, Government College Women University, Sialkot, Pakistan

E-mail: sadia.maalik@gcwus.edu.pk

Received: 19 February 2026  Accepted: 2 May 2026

Abstract:

Organophosphate pesticides are widely used in agriculture and may pose significant risks to pollinators such as Apis mellifera. The present study evaluated the acute toxicity and sublethal cytogenetic effects of dichlorvos (DDVP) in adult worker honeybees using mortality assessment and micronucleus-based nuclear abnormality analysis. Worker bees were collected from agricultural fields in Sialkot, Pakistan, and exposed under laboratory conditions (25 ± 2 °C; 60 ± 5% RH) to dichlorvos concentrations ranging from 1 to 40 µL/L. Mortality was recorded after 24 h, LC₅₀ was estimated by probit analysis, and hemocytes from control and exposed bees were scored for micronuclei, nuclear buds, and binucleated cells. Results showed a clear dose-dependent increase in mortality, with 16.67 ± 4.71% mortality at 1 µL/L, 46.67 ± 4.71% at 10 µL/L, and 96.67 ± 4.71% at 40 µL/L; the LC₅₀ was estimated at 10 µL/L. Sublethal exposure also increased cytogenetic abnormalities relative to the control group. At 1/3 LC₅₀, micronuclei reached 5.0 ± 1.2% and total genomic damage 9.3 ± 1.7%, whereas at 1/7 LC₅₀, micronuclei were 2.1 ± 0.5% and total genomic damage was 3.9 ± 0.7%. Micronucleus frequency differed significantly among treatment groups (F₍3,8₎ = 341.00, p < 0.001). These findings indicate that dichlorvos exposure is associated with acute toxicity and increased cytogenetic abnormalities in honeybee hemocytes, highlighting the importance of including sublethal and cytogenetic endpoints in pesticide risk assessment and pollinator protection strategies.

Keywords: Acetylcholinesterase inhibition; Cytotoxicity; Hemocytes; Micronucleus assay; Pollinator health

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05010-1

Chemical Papers 80 (9) 10355–10364 (2026)