Ant-attended aphids are known to excrete high-quality honeydew when ants are present. Ant attendance has a negative effect on the growth and reproduction of the attended aphids. Therefore, trade-offs should occur between the quality of honeydew and the growth and fecundity of aphid individuals. Thus, if attending ants prefer the morph excreting a high-quality honeydew, such trade-offs and resulting competitive interactions are expected between the color morphs in M. yomogicola. The morph excreting high-quality honeydew is known to have a lower reproductive rate than the other morphs[9,10]. This fact implies that if the attending ants prefer one morph, this morph is expected to excrete high-quality honeydew. Note that any such difference between morphs leads to the exclusion of the inferior morphs. Surprisingly, nearly all colonies consist of both green and red morphs in the field.
In this paper, we do not challenge this claim. Instead, we presuppose its plausibility in order to explore what ethical consequences follow from it.
And further in the introduction
He has argued that, while animals probably lack the sorts of concepts and metacognitive capacities necessary to be held morally responsible for their behaviour, this only excludes them from the possibility of counting as moral agents. There are, however, certain moral motivations that, in his view, may be reasonably thought to fall within the reach of (at least some) animal species, namely, moral emotions such as “sympathy and compassion, kindness, tolerance, and patience, and also their negative counterparts such as anger, indignation, malice, and spite”, as well as “a sense of what is fair and what is not” (Rowlands 2012, 32). If animals do indeed behave on the basis of moral emotions, they should, he argues, be considered moral subjects, even if their lack of sophisticated cognitive capacities prevents us from holding them morally responsible.1
But yes, I am fairly certain that no non-human animals has the mental facilities to be true moral agents. Especially because this is something a significant chunk of humans struggle with, and no animal comes close to us in terms of abstract thinking and that kinda stuff.