Q.24 In a honey bee population, the workers are infertile but protect the queen from
intruders and help in reproduction. This is an example of
(A) K selection
(B) Sexual selection
(C) Kin selection
(D) Disruptive selection
Honey bee workers exhibit altruism by forgoing reproduction to protect the queen and aid her offspring production, which shares their genes, making this a classic case of kin selection.
Option Explanations
K Selection: Refers to species with low reproductive rates, investing heavily in few offspring for high survival in stable environments, like elephants. Honey bee workers’ infertility does not match this r/K life history strategy.
Sexual Selection: Involves traits enhancing mating success, such as peacock tails, through mate choice or competition. Worker sterility and protection behavior lack any reproductive competition element.
Kin Selection: Describes altruism toward relatives to boost inclusive fitness, per Hamilton’s rule (rB > C, where r is relatedness, B benefit, C cost). Workers (sisters to queen’s daughters, r=0.75 due to haplodiploidy) sacrifice reproduction to help queen’s offspring, propagating shared genes.
Disruptive Selection: Favors population extremes over intermediates, leading to bimodal traits, as in finch beak sizes. No such trait variation occurs in uniform worker altruism.
Introduction
In honey bee populations, workers are infertile but protect the queen from intruders and help in reproduction—this kin selection example highlights altruistic evolution in eusocial insects. Key phrase: “kin selection honey bee population workers protect queen.” Ideal for CSIR NET Life Sciences aspirants studying evolutionary biology.
Understanding Kin Selection
Kin selection explains how natural selection favors traits benefiting relatives’ reproduction, even at personal cost, via inclusive fitness. In honey bees (Apis mellifera), haplodiploid genetics makes sisters share 75% genes, so workers prioritize queen’s daughters over personal offspring. Hamilton’s rule (rB > C) quantifies this: high relatedness (r) justifies sacrifice (C) for queen’s reproductive gain (B).
Honey Bee Social Structure
Queen lays fertilized (female) and unfertilized (drone) eggs; workers (diploid females) forage, guard, and nurse larvae but remain sterile. This eusociality evolved through kin selection, as workers boost indirect fitness by raising sisters (future queens/workers). Disruptive threats trigger stinging defense, often fatal to workers.
Why Not Other Selections?
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K Selection: Density-independent, few offspring strategy—not applicable to honey bees’ high brood production.
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Sexual Selection: Mating-driven—no role in sterile workers.
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Disruptive Selection: Bimodal trait favoring—not seen in uniform castes.
| Selection Type | Key Feature | Honey Bee Fit? |
|---|---|---|
| K Selection | Few, cared-for offspring | No—mass reproduction |
| Sexual Selection | Mate attraction/competition | No—workers infertile |
| Kin Selection | Altruism to relatives | Yes—protect queen’s kin |
| Disruptive Selection | Extreme trait favor | No—caste uniformity |
CSIR NET Relevance
This question tests evolutionary ecology; kin selection integrates genetics, behavior, and haplodiploidy. Practice: Recall Hamilton’s rule for similar MCQs on eusociality in ants/bees.
