In which of the following organisms is the phenomenon observed where the female sometimes kills and eats the male after copulation, a behaviour known as sexual cannibalism?

Introduction / Context:
In the animal kingdom, mating behaviours can be very diverse and sometimes extreme. One well known and dramatic behaviour is sexual cannibalism, in which the female kills and may eat the male after or during copulation. This behaviour has been observed in several invertebrate groups. General knowledge and basic biology questions often focus on identifying which type of organism is best known for this phenomenon. This question asks you to select that organism from four options.

Given Data / Assumptions:

• The behaviour described is that the female kills the male after copulation.
• The options given are Dragonfly, Honeybee, Spider, and Pit viper.
• We assume a school level understanding of famous examples of sexual cannibalism.
• We also assume basic knowledge of the difference between insects, arachnids, and reptiles.

Concept / Approach:
Spiders, particularly certain species such as the black widow, are classic examples of sexual cannibalism. In some species, the female may attack and consume the male after mating, which is thought to provide nutritional benefits or be linked to mating strategies. Dragonflies and honeybees do not typically exhibit this kind of post copulatory killing by the female. Pit vipers are reptiles and are not known for sexual cannibalism in this sense. Therefore, the approach is to recall that spiders are the textbook case associated with this dramatic behaviour.

Step-by-Step Solution:
Step 1: Identify the behaviour described: the female kills and sometimes eats the male after mating. Step 2: Recall that this pattern is widely discussed in relation to spiders, especially black widow and some other spider species. Step 3: Consider dragonflies, which have complex mating flights and positions but are not known for females killing males after copulation as a regular pattern. Step 4: Consider honeybees. Male drones die after mating because of physical damage, but this is not female initiated killing and is not generally referred to as sexual cannibalism. Step 5: Recognise that pit vipers are reptiles with different reproductive habits and are not associated with this behaviour. Therefore, select Spider as the correct answer.

Verification / Alternative check:
To verify, think of common illustrations in biology textbooks and documentaries that show a female spider attacking the male after mating. This image is so widely used that terms like black widow have become part of everyday language to describe dangerous mates. You will rarely see similar representations for dragonflies, honeybees, or snakes in the context of post mating cannibalism. The repeated emphasis on spiders as the standard example confirms that spider is the intended answer in such questions.

Why Other Options Are Wrong:
Dragonfly is wrong because its mating behaviour involves tandem flight and oviposition but not systematic killing of the male by the female. Honeybee is incorrect because while drone males do die after mating, this is due to the mechanics of mating and not because the female actively kills and eats them. Pit viper is also wrong; snakes may show territorial or mating aggression but sexual cannibalism is not a characteristic behaviour in this group. None of these alternatives match the specific phenomenon of the female killing the male after copulation in the way spiders do.

Common Pitfalls:
A common pitfall is to over interpret the idea that male honeybees die after mating and assume that any death after copulation must be the same concept as sexual cannibalism. Another mistake is to associate aggression in reptiles like snakes with mating behaviours without concrete examples. To avoid confusion, remember that sexual cannibalism as a named behaviour is most strongly linked to some spiders and certain mantis species, and in this particular option set, spiders are the clear representative of that pattern.

Final Answer:
The correct answer is Spider, because spiders are well known for cases where the female kills and sometimes eats the male after copulation, a behaviour described as sexual cannibalism.