What are the chemical messages called that influence the behavior of other members of a species, often related to mating or alarm signals?

The correct answer is pheromones, which are chemical signals secreted by an individual that can affect the behavior of other individuals of the same species. Pheromones play a crucial role in various social behaviors, particularly in mating rituals and communication about danger or alarm. They are detected through the vomeronasal organ and can trigger specific reproductive or defensive responses in others, facilitating reproduction or alerting a group to threats.

Hormones, while also chemical messengers, function primarily within the individual’s body to regulate internal processes such as growth, metabolism, and mood, rather than influencing the behavior of others externally. Neurotransmitters are chemicals that transmit signals across synapses in the nervous system, mainly affecting communication between neurons within an individual rather than between members of a species. Endorphins serve as natural pain relievers and mood enhancers but do not primarily act as signals to affect the behavior of others in a social context.