TY  - JOUR
JF  - Acarologia
T1  - Effect of group rearing on the life table parameters of the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae)
VL  - 66
IS  - 1
SP  - 118
EP  - 133
PY  - 2026
SN  - 0044-586X
SN  - 2107-7207
PB  - Les Amis d'Acarologia
AU  - Hayder, Tasfia
AU  - Meem, Mst. Masuma Momtaj
AU  - Tonni, Farhana Akter
AU  - Nikson, A. K.
AU  - Gotoh, Tetsuo
AU  - Ullah, Mohammad Shaef
UR  - https://doi.org/10.24349/uhbs-wb0j
DO  - 10.24349/uhbs-wb0j
DA  - 2026-02-13
ET  - 2026-02-13
KW  - Tetranychus urticae
KW  - group rearing
KW  - density-dependence
KW  - fecundity
KW  - demographic parameters
AB  - Effect of group size on life table parameters of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) was assessed using an age-stage, two-sex life table analysis. One (single), 2 (double), 4 (quadruple), and 6 (sextuple) individuals were placed on leaf discs, under controlled conditions like 25℃, 60-80% RH and a 16L: 8D photoperiod. Leaf discs of varying sizes, e.g., of 8, 11, 16, and 20 mm were used to maintain approximately equal mite densities, allowing us to evaluate the impact of conspecific presence on mite behavior without confounding effects related to density. Both male and female T. urticae successfully completed development under all rearing conditions, confirming that the experimental setup was suitable for subsequent evaluation of density effects on life-history traits and life table parameters. Rearing density significantly affected several life-history traits of T. urticae. The average pre-oviposition period decreased from 2.29 days in singly reared females to 1.66  days in the sextuple group, while oviposition duration increased from 8.29 to 13.62 days. Female longevity and fecundity were highest in the sextuple treatment, with females producing 82.00 eggs compared with 34.45 eggs in the single treatment. Demographic parameters were also significantly influenced by rearing density. The net reproductive rate (R₀) increased from 15.71 in singly reared mites to 45.88 in the sextuple group, and the intrinsic rate of increase (r) rose from 0.1340 to 0.1858 day⁻¹. Similarly, the finite rate of increase (λ) increased from 1.1434 to 1.2042 day⁻¹, indicating enhanced population growth at higher rearing densities. These results demonstrate that rearing density strongly influences life-history traits and population growth parameters of T. urticae, with single rearing producing significantly lower reproductive output and intrinsic growth rates compared with group-rearing conditions. This study underscores the significance of group size on the life parameters of T. urticae, which has potential implications for better pest management.
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