This is the mono bug team I've been running as of late. I have mixed luck, sometimes getting stomped and other times sweeping entire teams. This team actually seems to work better in Ubers for me, but I'd like to start destroying things in UU with it.
Ledian (M) @ Focus Sash
Trait: Iron Fist
EVs: 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Light Screen
- Reflect
- Mach Punch
- Protect
Yep. A Ledian lead. Something you never see. Funnily enough, he's been very reliable for me. He can outspeed a lot of leads, and has the sash just in case he's hit hard right off the bat. Ideally, he puts up dual screens and switches out. He can be a nice suicide lead, but it's better to keep him around to revenge kill annoying sashed Pokemon with Mach Punch.
Heracross (M) @ Choice Scarf Trait: Moxie
EVs: 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Earthquake
- Megahorn
- Rock Slide
- Close Combat
I've replaced Pinsir with Heracross, due to Hera's better Attack stat. Pretty much the same Scarf Moxie Sweep set, with obvious coverage. He outspeeds many threats and after one or two boosts from Moxie becomes an unbelievable physical monster. Rock Slide is in place of Stone Edge due to much better Accuracy and chance of flinch.
Volbeat (M) @ Leftovers
Trait: Prankster
EVs: 252 HP / 172 Def / 84 SDef
Bold Nature (+Def, -Atk)
- Baton Pass
- Tail Glow
- Thunder Wave
- Substitute
Prankster is the best thing ever for poor Volbeat. He's gone from useless to an AMAZING Baton Passer. With screens up he's extremely bulky, and ideally will be able to pass two Tail Glows to Accelgor (see below). If not, he's always useful for popping in and using Thunder Wave on things, or passing a sub to someone who needs it. (Pinsir, anyone?)
Accelgor (M) @ Focus Sash
Trait: Unburden
EVs: 4 HP / 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Bug Buzz
- Energy Ball
- Focus Blast
- Hidden Power [Ice]
Oh man. Accelgor. Overlooked and underestimated by most. Normally he can dish out pretty good attacks, but his frailty makes him undesirable. However, he becomes a destroyer of worlds with two Tail Glows passed to him, with a breathtaking 1312 Sp Atk. He can easily ohko 90% of Pokemon, including Ubers. Just in case he's outsped by something scarfed (Garchomp, anyone?), he has a sash and Unburden, his speed easily breaking 700 so he can outspeed anything in the metagame. Sadly, that tactic does not work under sandstorm, hail, or against an opponent with priority. However, unprepared opponents will have their entire teams swept with ease. Bug Buzz is for STAB, Energy Ball is mainly for bulky waters, Focus Blast is for annoying Steel and Rock-types, and HP Ice makes short work of those powerful dragons.
Pineco (M) @ Eviolite
Trait: Sturdy
EVs: 252 HP / 4 Def / 252 SDef
Careful Nature (+SDef, -SAtk)
- Stealth Rock
- Rapid Spin
- Reflect
- Light Screen
Eviolite Pineco? What? Yes. A wonderful alternative to Forretress in UU, and usefully not 4x weak to fire like his evo. This is a pretty basic set. Dual screens to keep fragile Pinsir and Volbeat in the game, Stealth Rock to break sashes, and Rapid Spin to deal with the bane of bugs, Stealth Rock.
Shuckle (M) @ Leftovers
Trait: Sturdy
EVs: 252 HP / 124 Def / 132 SDef
Impish Nature (+Def, -SAtk)
- Power Split
- Acupressure
- Rollout
- Rest
The mighty boulder, Shuckle. This thing has swept entire Ubers teams by himself, and shouldn't be underestimated. After being switched in on something with atrociously high offenses, Power Share can be used to neuter the opponent, as well as give Shuckle a nice Atk boost. Acupressure spam comes afterward, ideally maxing Evasion, Defenses, and Attack. Rest away any status and damage, and use Rollout once Shuckle is prepared. Watch him totally destroy unprepared teams.
So, that's my mighty bug mono. All criticism and advice is appreciated. So far I've had few problems with this team, but it feels like it's missing something.

Ledian (M) @ Focus Sash
Trait: Iron Fist
EVs: 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Light Screen
- Reflect
- Mach Punch
- Protect
Yep. A Ledian lead. Something you never see. Funnily enough, he's been very reliable for me. He can outspeed a lot of leads, and has the sash just in case he's hit hard right off the bat. Ideally, he puts up dual screens and switches out. He can be a nice suicide lead, but it's better to keep him around to revenge kill annoying sashed Pokemon with Mach Punch.

Heracross (M) @ Choice Scarf Trait: Moxie
EVs: 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Earthquake
- Megahorn
- Rock Slide
- Close Combat
I've replaced Pinsir with Heracross, due to Hera's better Attack stat. Pretty much the same Scarf Moxie Sweep set, with obvious coverage. He outspeeds many threats and after one or two boosts from Moxie becomes an unbelievable physical monster. Rock Slide is in place of Stone Edge due to much better Accuracy and chance of flinch.

Volbeat (M) @ Leftovers
Trait: Prankster
EVs: 252 HP / 172 Def / 84 SDef
Bold Nature (+Def, -Atk)
- Baton Pass
- Tail Glow
- Thunder Wave
- Substitute
Prankster is the best thing ever for poor Volbeat. He's gone from useless to an AMAZING Baton Passer. With screens up he's extremely bulky, and ideally will be able to pass two Tail Glows to Accelgor (see below). If not, he's always useful for popping in and using Thunder Wave on things, or passing a sub to someone who needs it. (Pinsir, anyone?)

Accelgor (M) @ Focus Sash
Trait: Unburden
EVs: 4 HP / 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Bug Buzz
- Energy Ball
- Focus Blast
- Hidden Power [Ice]
Oh man. Accelgor. Overlooked and underestimated by most. Normally he can dish out pretty good attacks, but his frailty makes him undesirable. However, he becomes a destroyer of worlds with two Tail Glows passed to him, with a breathtaking 1312 Sp Atk. He can easily ohko 90% of Pokemon, including Ubers. Just in case he's outsped by something scarfed (Garchomp, anyone?), he has a sash and Unburden, his speed easily breaking 700 so he can outspeed anything in the metagame. Sadly, that tactic does not work under sandstorm, hail, or against an opponent with priority. However, unprepared opponents will have their entire teams swept with ease. Bug Buzz is for STAB, Energy Ball is mainly for bulky waters, Focus Blast is for annoying Steel and Rock-types, and HP Ice makes short work of those powerful dragons.

Pineco (M) @ Eviolite
Trait: Sturdy
EVs: 252 HP / 4 Def / 252 SDef
Careful Nature (+SDef, -SAtk)
- Stealth Rock
- Rapid Spin
- Reflect
- Light Screen
Eviolite Pineco? What? Yes. A wonderful alternative to Forretress in UU, and usefully not 4x weak to fire like his evo. This is a pretty basic set. Dual screens to keep fragile Pinsir and Volbeat in the game, Stealth Rock to break sashes, and Rapid Spin to deal with the bane of bugs, Stealth Rock.

Shuckle (M) @ Leftovers
Trait: Sturdy
EVs: 252 HP / 124 Def / 132 SDef
Impish Nature (+Def, -SAtk)
- Power Split
- Acupressure
- Rollout
- Rest
The mighty boulder, Shuckle. This thing has swept entire Ubers teams by himself, and shouldn't be underestimated. After being switched in on something with atrociously high offenses, Power Share can be used to neuter the opponent, as well as give Shuckle a nice Atk boost. Acupressure spam comes afterward, ideally maxing Evasion, Defenses, and Attack. Rest away any status and damage, and use Rollout once Shuckle is prepared. Watch him totally destroy unprepared teams.
So, that's my mighty bug mono. All criticism and advice is appreciated. So far I've had few problems with this team, but it feels like it's missing something.