GMAT Reading Comprehension (RC) | Re: A small number of the forest species of lepidoptera

Hi mikemcgarry or other experts,

I am afraid my interpretation is incorrect, but I have no idea what wrong I have.
Please help to correct.

In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.

I focus on this sentence when I sort of the weaken question.
I intended to make sure the relation of insect, agent, predatory birds or parasite.
I
...

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