IV. Reading-Comprehension & Mixed-Type Questions Design 10%
Please design 3 reading comprehension questions and 2 mixed-type questions (5 questions in total) that align with current GSAT competency-based assessment trends.
Recent research published in Current Biology documents an unusual and striking instance of social parasitism in ants, in which a queen of Lasius orientalis infiltrates and ultimately seizes control of a colony belonging to another species, Lasius flavus. Rather than killing the resident queen outright, the invading monarch manipulates the host workers into eliminating their own mother by subtly altering the chemical signals that govern nestmate recognition and maintain social order. First observed by ant enthusiast Taku Shimada and later formally examined in collaboration with ecologist Keizo Takasuka, the phenomenon is especially noteworthy because the Lasius flavus workers appear to gain no adaptive or evolutionary advantage from their actions; instead, the invading queen alone secures reproductive dominance and
long-term control of the colony’s resources.
To determine how such manipulation is possible, Shimada recreated the invasion process under controlled experimental conditions. A Lasius orientalis queen was first allowed to acquire the scent of Lasius flavus workers, a crucial step given that ants rely heavily on chemical cues to distinguish colony members from outsiders. Disguised by this acquired odor, the invader entered the nest without resistance and was not only tolerated but even provisioned with food. After locating the host queen, however, she sprayed her with a chemical substance, believed to be formic acid, thereby altering the queen’s scent profile and destabilizing the colony’s established recognition system.
This chemical disruption had profound behavioral consequences. Deprived of reliable sensory cues, the workers no longer identified their queen as kin and gradually exhibited signs of agitation and aggression. Repeated spraying intensified the hostility, and over the course of several days the workers
collectively turned against their mother and killed her. Shortly thereafter, they accepted the intruder as their new reproductive authority, effectively transferring allegiance without apparent resistance.
In the weeks that followed, the parasitic queen began laying eggs, and the colony’s composition progressively shifted until all workers were her offspring. Beyond its dramatic narrative, the study underscores the central role of chemical communication in sustaining social cohesion and demonstrates how subtle biochemical interference can overturn entrenched hierarchies within complex insect societies.