Insect Girl

The Insect Girl takes care of the logistics of a team. Mana is a precious resource that fuel magical spells and offensive tricks. The Insect Girl can hoard tremendous amount of mana and distribute it among her teammates, both in and out of combat.

Combat
Insect Girls are generalists with average stats across the board. They only have strong stat growth in mana capacity, which helps with efficient use of their fixed skill, ExtractMana. With their three open skill slots, they can be bred to serve a variety of combat roles while maintaining their mana/energy transfer abilities.

Their TransferMana onFuck passive allows them to recharge spell-casters, which is helpful especially in combination with Brood Queens/Lava Brood Queens (who receive double mana from being fucked), units like the Succubus with onGettingFucked passives, and any units with Abdomens like other Insect Girls.

With Abdomens, they don't lose energy when they get fucked, and they have a 75% chance to gain a point of energy if their partner lost energy, so they can collect energy in combat from both allies and enemies. An Insect Girl can move adjacent to an enemy with high lust and then use Seduce on itself to present itself and try to entice the enemy into fucking it. Their mediocre beauty stats don't give them much of a bonus to this, though, so they'll probably need assistance from other units with good seduction abilities to raise the target's lust.

Their Collector trait means that if they Service a male or futa enemy to completion, they can drain double the semen and energy, so they can choose between attempting to drain energy quickly and attempting to steal it.

Note that all of these abilities require an Insect Girl to be adjacent to an enemy to be used, so choose their equipment, skills, etc. expecting them to see front-line combat.

Overworld
Their Abdomen gives them the TransferEnergy overworld ability, which allows them to increase another character's energy by 1 at the cost of 2 of their own energy. This allows them to recharge the energy of non-Abdomen units, and it's less efficient but definitely safer than fucking another Abdomen unit during combat. This can help keep your main recruiter units from running out of energy on portal expeditions.

Breeding
They can produce eggs at the cost of 10 energy and stamina, effectively breeding with themselves to determine the genes and traits of the egg. The stability of eggs produced this way is halved for non-queens. Newly hatched/hired Insect Girls start with 10 energy, so they can immediately produce an egg right after they join your team if you want them to.

Their base fertility and virility is mediocre, but they have an energy capacity of 20, which gives them an additional +200% bonus to those stats when breeding while at 20 energy. A stock Insect Girl takes 20 days to completely refill on its own, though, so they're dependent on their energy stealing and transferring abilities to reasonably function for breeding.

Brood Queens and Lava Brood Queens have amazing fertility, good virility, and even higher energy capacity than Insect Girls, so instead of breeding Insect Girls with each other, it may be more effective to have your Insect Girls transfer their energy to brood queens so they can breed with each other. They could also transfer their energy to a particularly virile male or futa Insect Girl for breeding with the queen, for a 50/50 ratio of Insect Girls and queens in their offspring.

Because their base fertility and virility can be multiplied so much at high energy totals and insect breeding is so energy-intensive, having a variety of sizes for your Insect Girls may have a major impact on their breeding ability. A small female and a large male might produce significantly more eggs than two equal-sized units for the same amount of energy.

Moneymaking
Insect Girls have a low base beauty stat, but they have something else going for them when it comes to working at the brothel - they have four hands and they use all four at once during sex training sessions, which makes it very easy for them to gain massive Hand exp and cap-breaking bonus exp, with little stamina expenditure required from the main character.

They're a great addition to a gloryhole room where beauty isn't considered but sex skills count double, where their godlike quadruple handjob skills can attract large numbers of clients to help train new brothel workers' sex skills.

Trivia

 * Basic supporter for a Broodmother.
 * They can collect/store huge amounts of semen in their abdomen, to later gift to their queen.