American Indians would harvest grasshoppers in the early morning, while they were still lethargic from the night's chill. If you had enough people, and a large net with small mesh, I imagine you could "drive" them before you with a bunch of people beating the long grass with switches and then drive them into the net, held by 2 other folks.
But it's a good point to not expend more calories "catching" bugs than you'd get back. This makes the wood grubs I'm fond of not so great a resource. In a cord of wood, using a hydraulic splitter, I'll usually only see 2 to 5, and unless I came across some while splitting wood for my fire in the bush, they wouldn't be worth "looking" for. But any *found* calories can't be ignored. :~} From what I understand, Witchety and Suri grubs are actually fairly easy to find and harvest, provided one knows where to look. The locals eat them as part of their normal diets, not as "survival rations".
But it's a good point to not expend more calories "catching" bugs than you'd get back. This makes the wood grubs I'm fond of not so great a resource. In a cord of wood, using a hydraulic splitter, I'll usually only see 2 to 5, and unless I came across some while splitting wood for my fire in the bush, they wouldn't be worth "looking" for. But any *found* calories can't be ignored. :~} From what I understand, Witchety and Suri grubs are actually fairly easy to find and harvest, provided one knows where to look. The locals eat them as part of their normal diets, not as "survival rations".